diff --git a/Gemfile b/Gemfile
index 29368642..5a6898b0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,7 +3,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 ruby ">= 2.4.10", "< 2.5"
 
-gem "rails", "~> 5.0.7.2"
+gem "rails", "~> 5.1.7"
 
 gem "devise", "~> 4.0"
 gem "psych", "~> 2.0.2" # part of stdlib, need newer version for safe_load
@@ -24,7 +24,7 @@ gem "loofah", "<= 2.20.0"
 gem "whenever", require: false # for cron jobs
 gem "tilt"
 gem "simple-navigation", "3.11.0"
-gem "simple_form", "3.3.1"
+gem "simple_form", "~> 4.1.0"
 gem "render_anywhere"
 gem "pygments.rb", "~> 2.0"
 gem "ranked-model"
diff --git a/Gemfile.lock b/Gemfile.lock
index fc8a014b..c22e2bd6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -17,43 +17,43 @@ GEM
   remote: https://rubygems.org/
   specs:
     Ascii85 (1.1.1)
-    actioncable (5.0.7.2)
-      actionpack (= 5.0.7.2)
-      nio4r (>= 1.2, < 3.0)
+    actioncable (5.1.7)
+      actionpack (= 5.1.7)
+      nio4r (~> 2.0)
       websocket-driver (~> 0.6.1)
-    actionmailer (5.0.7.2)
-      actionpack (= 5.0.7.2)
-      actionview (= 5.0.7.2)
-      activejob (= 5.0.7.2)
+    actionmailer (5.1.7)
+      actionpack (= 5.1.7)
+      actionview (= 5.1.7)
+      activejob (= 5.1.7)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.0.7.2)
-      actionview (= 5.0.7.2)
-      activesupport (= 5.0.7.2)
+    actionpack (5.1.7)
+      actionview (= 5.1.7)
+      activesupport (= 5.1.7)
       rack (~> 2.0)
-      rack-test (~> 0.6.3)
+      rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.0.7.2)
-      activesupport (= 5.0.7.2)
+    actionview (5.1.7)
+      activesupport (= 5.1.7)
       builder (~> 3.1)
-      erubis (~> 2.7.0)
+      erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.0.7.2)
-      activesupport (= 5.0.7.2)
+    activejob (5.1.7)
+      activesupport (= 5.1.7)
       globalid (>= 0.3.6)
-    activemodel (5.0.7.2)
-      activesupport (= 5.0.7.2)
+    activemodel (5.1.7)
+      activesupport (= 5.1.7)
     activemodel-serializers-xml (1.0.3)
       activemodel (>= 5.0.0.a)
       activesupport (>= 5.0.0.a)
       builder (~> 3.1)
-    activerecord (5.0.7.2)
-      activemodel (= 5.0.7.2)
-      activesupport (= 5.0.7.2)
-      arel (~> 7.0)
-    activesupport (5.0.7.2)
+    activerecord (5.1.7)
+      activemodel (= 5.1.7)
+      activesupport (= 5.1.7)
+      arel (~> 8.0)
+    activesupport (5.1.7)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
@@ -63,7 +63,7 @@ GEM
     afm (0.2.2)
     airbrussh (1.5.3)
       sshkit (>= 1.6.1, != 1.7.0)
-    arel (7.1.4)
+    arel (8.0.0)
     ast (2.4.3)
     atomic (1.1.101)
     avl_tree (1.2.1)
@@ -129,13 +129,12 @@ GEM
       railties (>= 4.1.0)
       responders
       warden (~> 1.2.3)
-    diff-lcs (1.6.1)
+    diff-lcs (1.6.2)
     docile (1.3.5)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
     ed25519 (1.3.0)
     erubi (1.13.1)
-    erubis (2.7.0)
     eventmachine (1.2.7)
     execjs (2.9.0)
     factory_bot (5.2.0)
@@ -181,10 +180,10 @@ GEM
       atomic (~> 1.0)
       avl_tree (~> 1.2.0)
       hitimes (~> 1.1)
-    mime-types (3.6.2)
+    mime-types (3.7.0)
       logger
-      mime-types-data (~> 3.2015)
-    mime-types-data (3.2025.0415)
+      mime-types-data (~> 3.2025, >= 3.2025.0507)
+    mime-types-data (3.2025.0701)
     mini_mime (1.1.2)
     mini_portile2 (2.4.0)
     mini_racer (0.4.0)
@@ -193,8 +192,8 @@ GEM
     mustermann (2.0.2)
       ruby2_keywords (~> 0.0.1)
     net-http-digest_auth (1.4.1)
-    net-http-persistent (4.0.5)
-      connection_pool (~> 2.2)
+    net-http-persistent (4.0.6)
+      connection_pool (~> 2.2, >= 2.2.4)
     net-scp (4.1.0)
       net-ssh (>= 2.6.5, < 8.0.0)
     net-sftp (4.0.0)
@@ -221,7 +220,7 @@ GEM
       ttfunk
     pdfkit (0.8.4.3.2)
     pg (1.2.3)
-    pkg-config (1.6.1)
+    pkg-config (1.6.2)
     prawn (2.2.2)
       pdf-core (~> 0.7.0)
       ttfunk (~> 1.5)
@@ -233,22 +232,22 @@ GEM
       activesupport (>= 3.0.0)
     pygments.rb (2.3.1)
     racc (1.5.2)
-    rack (2.2.13)
+    rack (2.2.17)
     rack-protection (2.2.3)
       rack
-    rack-test (0.6.3)
-      rack (>= 1.0)
-    rails (5.0.7.2)
-      actioncable (= 5.0.7.2)
-      actionmailer (= 5.0.7.2)
-      actionpack (= 5.0.7.2)
-      actionview (= 5.0.7.2)
-      activejob (= 5.0.7.2)
-      activemodel (= 5.0.7.2)
-      activerecord (= 5.0.7.2)
-      activesupport (= 5.0.7.2)
+    rack-test (2.2.0)
+      rack (>= 1.3)
+    rails (5.1.7)
+      actioncable (= 5.1.7)
+      actionmailer (= 5.1.7)
+      actionpack (= 5.1.7)
+      actionview (= 5.1.7)
+      activejob (= 5.1.7)
+      activemodel (= 5.1.7)
+      activerecord (= 5.1.7)
+      activesupport (= 5.1.7)
       bundler (>= 1.3.0)
-      railties (= 5.0.7.2)
+      railties (= 5.1.7)
       sprockets-rails (>= 2.0.0)
     rails-controller-testing (1.0.5)
       actionpack (>= 5.0.1.rc1)
@@ -260,9 +259,9 @@ GEM
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.5.0)
       loofah (~> 2.19, >= 2.19.1)
-    railties (5.0.7.2)
-      actionpack (= 5.0.7.2)
-      activesupport (= 5.0.7.2)
+    railties (5.1.7)
+      actionpack (= 5.1.7)
+      activesupport (= 5.1.7)
       method_source
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
@@ -338,9 +337,9 @@ GEM
       concurrent-ruby (~> 1.0, >= 1.0.2)
     simple-navigation (3.11.0)
       activesupport (>= 2.3.2)
-    simple_form (3.3.1)
-      actionpack (> 4, < 5.1)
-      activemodel (> 4, < 5.1)
+    simple_form (4.1.0)
+      actionpack (>= 5.0)
+      activemodel (>= 5.0)
     simplecov (0.18.5)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
@@ -446,7 +445,7 @@ DEPENDENCIES
   pundit (~> 1.1.0)
   pygments.rb (~> 2.0)
   qless!
-  rails (~> 5.0.7.2)
+  rails (~> 5.1.7)
   rails-controller-testing (~> 1.0)
   ranked-model
   recaptcha
@@ -462,7 +461,7 @@ DEPENDENCIES
   sd_notify
   sentry-rails
   simple-navigation (= 3.11.0)
-  simple_form (= 3.3.1)
+  simple_form (~> 4.1.0)
   simplecov
   sinatra
   spring
diff --git a/db/schema.rb b/db/schema.rb
index e5a82dd0..459469d1 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -15,145 +15,145 @@
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
-  create_table "contest_relations", force: :cascade do |t|
-    t.integer  "user_id"
-    t.integer  "contest_id"
+  create_table "contest_relations", id: :serial, force: :cascade do |t|
+    t.integer "user_id"
+    t.integer "contest_id"
     t.datetime "started_at"
     t.datetime "created_at"
     t.datetime "updated_at"
     t.datetime "finish_at"
-    t.integer  "score",                   default: 0,     null: false
-    t.float    "time_taken",              default: 0.0,   null: false
-    t.integer  "school_id"
-    t.integer  "status",                  default: 0
-    t.integer  "extra_time",              default: 0
+    t.integer "score", default: 0, null: false
+    t.float "time_taken", default: 0.0, null: false
+    t.integer "school_id"
+    t.integer "status", default: 0
+    t.integer "extra_time", default: 0
     t.datetime "start_time"
     t.datetime "end_time"
-    t.string   "country_code",  limit: 2
-    t.integer  "school_year"
-    t.integer  "supervisor_id"
-    t.boolean  "checked_in",              default: false
-    t.index ["contest_id", "score", "time_taken"], name: "index_contest_relations_on_contest_id_and_score_and_time_taken", order: { score: :desc }, using: :btree
-    t.index ["contest_id", "user_id"], name: "index_contest_relations_on_contest_id_and_user_id", unique: true, using: :btree
-    t.index ["user_id", "started_at"], name: "index_contest_relations_on_user_id_and_started_at", using: :btree
-  end
-
-  create_table "contest_scores", force: :cascade do |t|
-    t.integer  "contest_relation_id", null: false
-    t.integer  "problem_id",          null: false
-    t.integer  "score"
-    t.integer  "attempts"
-    t.integer  "attempt"
-    t.integer  "submission_id"
+    t.string "country_code", limit: 2
+    t.integer "school_year"
+    t.integer "supervisor_id"
+    t.boolean "checked_in", default: false
+    t.index ["contest_id", "score", "time_taken"], name: "index_contest_relations_on_contest_id_and_score_and_time_taken", order: { score: :desc }
+    t.index ["contest_id", "user_id"], name: "index_contest_relations_on_contest_id_and_user_id", unique: true
+    t.index ["user_id", "started_at"], name: "index_contest_relations_on_user_id_and_started_at"
+  end
+
+  create_table "contest_scores", id: :serial, force: :cascade do |t|
+    t.integer "contest_relation_id", null: false
+    t.integer "problem_id", null: false
+    t.integer "score"
+    t.integer "attempts"
+    t.integer "attempt"
+    t.integer "submission_id"
     t.datetime "updated_at"
-    t.index ["contest_relation_id", "problem_id"], name: "index_contest_scores_on_contest_relation_id_and_problem_id", using: :btree
+    t.index ["contest_relation_id", "problem_id"], name: "index_contest_scores_on_contest_relation_id_and_problem_id"
   end
 
-  create_table "contest_supervisors", force: :cascade do |t|
-    t.integer  "contest_id"
-    t.integer  "user_id"
-    t.string   "site_type",            limit: 255
-    t.integer  "site_id"
+  create_table "contest_supervisors", id: :serial, force: :cascade do |t|
+    t.integer "contest_id"
+    t.integer "user_id"
+    t.string "site_type", limit: 255
+    t.integer "site_id"
     t.datetime "created_at"
     t.datetime "updated_at"
     t.datetime "scheduled_start_time"
   end
 
-  create_table "contests", force: :cascade do |t|
-    t.string   "name",                           limit: 255
+  create_table "contests", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
     t.datetime "start_time"
     t.datetime "end_time"
-    t.decimal  "duration"
-    t.integer  "owner_id"
+    t.decimal "duration"
+    t.integer "owner_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "problem_set_id"
+    t.integer "problem_set_id"
     t.datetime "finalized_at"
-    t.string   "startcode",                      limit: 255
-    t.integer  "observation",                                default: 1
-    t.integer  "registration",                               default: 0
-    t.integer  "affiliation",                                default: 0
-    t.boolean  "live_scoreboard",                            default: true
-    t.boolean  "only_rank_official_contestants",             default: false
+    t.string "startcode", limit: 255
+    t.integer "observation", default: 1
+    t.integer "registration", default: 0
+    t.integer "affiliation", default: 0
+    t.boolean "live_scoreboard", default: true
+    t.boolean "only_rank_official_contestants", default: false
   end
 
-  create_table "entities", force: :cascade do |t|
-    t.string  "name",        limit: 255
+  create_table "entities", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
     t.integer "entity_id"
-    t.string  "entity_type", limit: 255
+    t.string "entity_type", limit: 255
   end
 
-  create_table "evaluators", force: :cascade do |t|
-    t.string   "name",        limit: 255,              null: false
-    t.text     "description",             default: "", null: false
-    t.text     "source",                  default: "", null: false
-    t.integer  "owner_id",                             null: false
+  create_table "evaluators", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255, null: false
+    t.text "description", default: "", null: false
+    t.text "source", default: "", null: false
+    t.integer "owner_id", null: false
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "language_id"
+    t.integer "language_id"
   end
 
-  create_table "file_attachments", force: :cascade do |t|
-    t.string   "name",            limit: 255
-    t.string   "file_attachment", limit: 255
-    t.integer  "owner_id"
-    t.datetime "created_at",                  null: false
-    t.datetime "updated_at",                  null: false
+  create_table "file_attachments", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
+    t.string "file_attachment", limit: 255
+    t.integer "owner_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
-  create_table "filelinks", force: :cascade do |t|
-    t.integer  "root_id"
-    t.integer  "file_attachment_id"
+  create_table "filelinks", id: :serial, force: :cascade do |t|
+    t.integer "root_id"
+    t.integer "file_attachment_id"
     t.datetime "created_at"
-    t.string   "filepath",           limit: 255
-    t.string   "root_type",          limit: 255
-    t.integer  "visibility",         limit: 2,   default: 0
-    t.index ["file_attachment_id"], name: "index_filelinks_on_file_attachment_id", using: :btree
-    t.index ["root_id", "filepath"], name: "index_filelinks_on_root_id_and_filepath", using: :btree
+    t.string "filepath", limit: 255
+    t.string "root_type", limit: 255
+    t.integer "visibility", limit: 2, default: 0
+    t.index ["file_attachment_id"], name: "index_filelinks_on_file_attachment_id"
+    t.index ["root_id", "filepath"], name: "index_filelinks_on_root_id_and_filepath"
   end
 
   create_table "group_contests", force: :cascade do |t|
     t.integer "group_id"
     t.integer "contest_id"
-    t.index ["contest_id", "group_id"], name: "index_group_contests_on_contest_id_and_group_id", using: :btree
-    t.index ["group_id", "contest_id"], name: "index_group_contests_on_group_id_and_contest_id", using: :btree
+    t.index ["contest_id", "group_id"], name: "index_group_contests_on_contest_id_and_group_id"
+    t.index ["group_id", "contest_id"], name: "index_group_contests_on_group_id_and_contest_id"
   end
 
   create_table "group_memberships", force: :cascade do |t|
-    t.integer  "group_id"
-    t.integer  "member_id"
+    t.integer "group_id"
+    t.integer "member_id"
     t.datetime "created_at"
   end
 
   create_table "group_problem_sets", force: :cascade do |t|
     t.integer "group_id"
     t.integer "problem_set_id"
-    t.string  "name",           limit: 255
-    t.index ["group_id", "problem_set_id"], name: "index_group_problem_sets_on_group_id_and_problem_set_id", using: :btree
-    t.index ["problem_set_id", "group_id"], name: "index_group_problem_sets_on_problem_set_id_and_group_id", using: :btree
+    t.string "name", limit: 255
+    t.index ["group_id", "problem_set_id"], name: "index_group_problem_sets_on_group_id_and_problem_set_id"
+    t.index ["problem_set_id", "group_id"], name: "index_group_problem_sets_on_problem_set_id_and_group_id"
   end
 
-  create_table "groups", force: :cascade do |t|
-    t.string   "name",       limit: 255
+  create_table "groups", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "owner_id"
-    t.integer  "visibility",             default: 0, null: false
-    t.integer  "membership",             default: 0, null: false
+    t.integer "owner_id"
+    t.integer "visibility", default: 0, null: false
+    t.integer "membership", default: 0, null: false
   end
 
-  create_table "item_histories", force: :cascade do |t|
-    t.integer  "item_id"
-    t.boolean  "active"
-    t.integer  "action"
-    t.integer  "holder_id"
-    t.string   "data",       limit: 255
+  create_table "item_histories", id: :serial, force: :cascade do |t|
+    t.integer "item_id"
+    t.boolean "active"
+    t.integer "action"
+    t.integer "holder_id"
+    t.string "data", limit: 255
     t.datetime "acted_at"
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
-  create_table "items", force: :cascade do |t|
+  create_table "items", id: :serial, force: :cascade do |t|
     t.integer "product_id"
     t.integer "owner_id"
     t.integer "organisation_id"
@@ -165,101 +165,101 @@
     t.integer "scan_token"
   end
 
-  create_table "language_groups", force: :cascade do |t|
-    t.string   "identifier",          limit: 255
-    t.string   "name",                limit: 255
-    t.integer  "current_language_id"
-    t.datetime "created_at",                      null: false
-    t.datetime "updated_at",                      null: false
-    t.index ["identifier"], name: "index_language_groups_on_identifier", unique: true, using: :btree
-  end
-
-  create_table "languages", force: :cascade do |t|
-    t.string   "identifier",          limit: 255
-    t.string   "compiler",            limit: 255
-    t.boolean  "interpreted"
-    t.datetime "created_at",                                  null: false
-    t.datetime "updated_at",                                  null: false
-    t.string   "extension",           limit: 255
-    t.boolean  "compiled"
-    t.string   "name",                limit: 255
-    t.string   "lexer",               limit: 255
-    t.integer  "group_id"
-    t.string   "source_filename",     limit: 255
-    t.string   "exe_extension",       limit: 255
-    t.string   "compiler_command",    limit: 255
-    t.string   "interpreter",         limit: 255
-    t.string   "interpreter_command", limit: 255
-    t.integer  "processes",                       default: 1
-    t.index ["identifier"], name: "index_languages_on_identifier", unique: true, using: :btree
-  end
-
-  create_table "organisations", force: :cascade do |t|
-  end
-
-  create_table "problem_series", force: :cascade do |t|
-    t.string "name",          limit: 255
-    t.string "identifier",    limit: 255
+  create_table "language_groups", id: :serial, force: :cascade do |t|
+    t.string "identifier", limit: 255
+    t.string "name", limit: 255
+    t.integer "current_language_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["identifier"], name: "index_language_groups_on_identifier", unique: true
+  end
+
+  create_table "languages", id: :serial, force: :cascade do |t|
+    t.string "identifier", limit: 255
+    t.string "compiler", limit: 255
+    t.boolean "interpreted"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.string "extension", limit: 255
+    t.boolean "compiled"
+    t.string "name", limit: 255
+    t.string "lexer", limit: 255
+    t.integer "group_id"
+    t.string "source_filename", limit: 255
+    t.string "exe_extension", limit: 255
+    t.string "compiler_command", limit: 255
+    t.string "interpreter", limit: 255
+    t.string "interpreter_command", limit: 255
+    t.integer "processes", default: 1
+    t.index ["identifier"], name: "index_languages_on_identifier", unique: true
+  end
+
+  create_table "organisations", id: :serial, force: :cascade do |t|
+  end
+
+  create_table "problem_series", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
+    t.string "identifier", limit: 255
     t.string "importer_type", limit: 255
-    t.text   "index_yaml"
+    t.text "index_yaml"
   end
 
   create_table "problem_set_problems", force: :cascade do |t|
     t.integer "problem_set_id"
     t.integer "problem_id"
     t.integer "problem_set_order"
-    t.integer "weighting",         default: 100
-    t.index ["problem_id", "problem_set_id"], name: "index_problem_set_problems_on_problem_id_and_problem_set_id", using: :btree
-    t.index ["problem_set_id", "problem_id"], name: "index_problem_set_problems_on_problem_set_id_and_problem_id", using: :btree
+    t.integer "weighting", default: 100
+    t.index ["problem_id", "problem_set_id"], name: "index_problem_set_problems_on_problem_id_and_problem_set_id"
+    t.index ["problem_set_id", "problem_id"], name: "index_problem_set_problems_on_problem_set_id_and_problem_id"
   end
 
-  create_table "problem_sets", force: :cascade do |t|
-    t.string   "name",                     limit: 255
-    t.integer  "owner_id"
+  create_table "problem_sets", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
+    t.integer "owner_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "finalized_contests_count",             default: 0
+    t.integer "finalized_contests_count", default: 0
   end
 
-  create_table "problems", force: :cascade do |t|
-    t.string   "name",               limit: 255
-    t.text     "statement"
-    t.string   "input",              limit: 255
-    t.string   "output",             limit: 255
-    t.integer  "memory_limit"
-    t.decimal  "time_limit"
-    t.integer  "owner_id"
+  create_table "problems", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
+    t.text "statement"
+    t.string "input", limit: 255
+    t.string "output", limit: 255
+    t.integer "memory_limit"
+    t.decimal "time_limit"
+    t.integer "owner_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "evaluator_id"
+    t.integer "evaluator_id"
     t.datetime "rejudge_at"
-    t.integer  "test_error_count",               default: 0
-    t.integer  "test_warning_count",             default: 0
-    t.integer  "test_status",                    default: 0
+    t.integer "test_error_count", default: 0
+    t.integer "test_warning_count", default: 0
+    t.integer "test_status", default: 0
   end
 
-  create_table "products", force: :cascade do |t|
-    t.string "name",        limit: 255
+  create_table "products", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
     t.bigint "gtin"
-    t.text   "description"
-    t.string "image",       limit: 255
+    t.text "description"
+    t.string "image", limit: 255
   end
 
-  create_table "requests", force: :cascade do |t|
-    t.integer  "requester_id"
-    t.integer  "subject_id"
-    t.string   "subject_type", limit: 255
-    t.string   "verb",         limit: 255,                      null: false
-    t.integer  "target_id",                                     null: false
-    t.string   "target_type",  limit: 255,                      null: false
-    t.integer  "status",                   default: 0,          null: false
-    t.integer  "requestee_id"
-    t.datetime "expired_at",               default: 'Infinity', null: false
-    t.datetime "created_at",                                    null: false
-    t.datetime "updated_at",                                    null: false
+  create_table "requests", id: :serial, force: :cascade do |t|
+    t.integer "requester_id"
+    t.integer "subject_id"
+    t.string "subject_type", limit: 255
+    t.string "verb", limit: 255, null: false
+    t.integer "target_id", null: false
+    t.string "target_type", limit: 255, null: false
+    t.integer "status", default: 0, null: false
+    t.integer "requestee_id"
+    t.datetime "expired_at", default: "Infinity", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
-  create_table "roles", force: :cascade do |t|
+  create_table "roles", id: :serial, force: :cascade do |t|
     t.string "name", limit: 255
   end
 
@@ -268,129 +268,129 @@
     t.integer "user_id"
   end
 
-  create_table "schools", force: :cascade do |t|
-    t.string  "name",         limit: 255
-    t.string  "country_code", limit: 2
+  create_table "schools", id: :serial, force: :cascade do |t|
+    t.string "name", limit: 255
+    t.string "country_code", limit: 2
     t.integer "users_count"
     t.integer "synonym_id"
   end
 
-  create_table "sessions", force: :cascade do |t|
-    t.string   "session_id", limit: 255, null: false
-    t.text     "data"
+  create_table "sessions", id: :serial, force: :cascade do |t|
+    t.string "session_id", limit: 255, null: false
+    t.text "data"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.index ["created_at"], name: "index_sessions_on_created_at", using: :btree
-    t.index ["session_id"], name: "index_sessions_on_session_id", using: :btree
-    t.index ["updated_at"], name: "index_sessions_on_updated_at", using: :btree
+    t.index ["created_at"], name: "index_sessions_on_created_at"
+    t.index ["session_id"], name: "index_sessions_on_session_id"
+    t.index ["updated_at"], name: "index_sessions_on_updated_at"
   end
 
-  create_table "settings", force: :cascade do |t|
-    t.string "key",   limit: 255
+  create_table "settings", id: :serial, force: :cascade do |t|
+    t.string "key", limit: 255
     t.string "value", limit: 255
-    t.index ["key"], name: "index_settings_on_key", unique: true, using: :btree
+    t.index ["key"], name: "index_settings_on_key", unique: true
   end
 
-  create_table "submissions", force: :cascade do |t|
-    t.text     "source"
-    t.integer  "score"
-    t.integer  "user_id"
-    t.integer  "problem_id"
+  create_table "submissions", id: :serial, force: :cascade do |t|
+    t.text "source"
+    t.integer "score"
+    t.integer "user_id"
+    t.integer "problem_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "input",          limit: 255
-    t.string   "output",         limit: 255
-    t.integer  "language_id"
-    t.text     "judge_log"
+    t.string "input", limit: 255
+    t.string "output", limit: 255
+    t.integer "language_id"
+    t.text "judge_log"
     t.datetime "judged_at"
-    t.string   "job",            limit: 255
-    t.integer  "classification"
-    t.string   "test_errors",    limit: 255, array: true
-    t.string   "test_warnings",  limit: 255, array: true
-    t.float    "evaluation"
-    t.decimal  "points"
-    t.integer  "maximum_points"
-    t.index ["problem_id", "created_at"], name: "index_submissions_on_problem_id_and_created_at", using: :btree
-    t.index ["user_id", "problem_id"], name: "index_submissions_on_user_id_and_problem_id", using: :btree
-  end
-
-  create_table "test_case_relations", force: :cascade do |t|
-    t.integer  "test_case_id"
-    t.integer  "test_set_id"
-    t.datetime "created_at",   null: false
-    t.datetime "updated_at",   null: false
-    t.index ["test_case_id"], name: "index_test_case_relations_on_test_case_id", using: :btree
-    t.index ["test_set_id"], name: "index_test_case_relations_on_test_set_id", using: :btree
-  end
-
-  create_table "test_cases", force: :cascade do |t|
-    t.text     "input"
-    t.text     "output"
-    t.string   "name",          limit: 255
+    t.string "job", limit: 255
+    t.integer "classification"
+    t.string "test_errors", limit: 255, array: true
+    t.string "test_warnings", limit: 255, array: true
+    t.float "evaluation"
+    t.decimal "points"
+    t.integer "maximum_points"
+    t.index ["problem_id", "created_at"], name: "index_submissions_on_problem_id_and_created_at"
+    t.index ["user_id", "problem_id"], name: "index_submissions_on_user_id_and_problem_id"
+  end
+
+  create_table "test_case_relations", id: :serial, force: :cascade do |t|
+    t.integer "test_case_id"
+    t.integer "test_set_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["test_case_id"], name: "index_test_case_relations_on_test_case_id"
+    t.index ["test_set_id"], name: "index_test_case_relations_on_test_set_id"
+  end
+
+  create_table "test_cases", id: :serial, force: :cascade do |t|
+    t.text "input"
+    t.text "output"
+    t.string "name", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "problem_id"
-    t.boolean  "sample",                    default: false
-    t.integer  "problem_order"
-    t.index ["problem_id", "name"], name: "index_test_cases_on_problem_id_and_name", unique: true, using: :btree
+    t.integer "problem_id"
+    t.boolean "sample", default: false
+    t.integer "problem_order"
+    t.index ["problem_id", "name"], name: "index_test_cases_on_problem_id_and_name", unique: true
   end
 
-  create_table "test_sets", force: :cascade do |t|
-    t.integer  "problem_id"
-    t.integer  "points"
-    t.string   "name",          limit: 255
+  create_table "test_sets", id: :serial, force: :cascade do |t|
+    t.integer "problem_id"
+    t.integer "points"
+    t.string "name", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.boolean  "prerequisite",              default: false
-    t.integer  "problem_order"
-    t.index ["problem_id", "name"], name: "index_test_sets_on_problem_id_and_name", unique: true, using: :btree
-  end
-
-  create_table "user_problem_relations", force: :cascade do |t|
-    t.integer  "problem_id"
-    t.integer  "user_id"
-    t.integer  "submissions_count"
-    t.integer  "ranked_score"
-    t.integer  "ranked_submission_id"
-    t.integer  "submission_id"
+    t.boolean "prerequisite", default: false
+    t.integer "problem_order"
+    t.index ["problem_id", "name"], name: "index_test_sets_on_problem_id_and_name", unique: true
+  end
+
+  create_table "user_problem_relations", id: :serial, force: :cascade do |t|
+    t.integer "problem_id"
+    t.integer "user_id"
+    t.integer "submissions_count"
+    t.integer "ranked_score"
+    t.integer "ranked_submission_id"
+    t.integer "submission_id"
     t.datetime "last_viewed_at"
     t.datetime "first_viewed_at"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.index ["problem_id", "ranked_score"], name: "index_user_problem_relations_on_problem_id_and_ranked_score", using: :btree
-    t.index ["user_id", "problem_id"], name: "index_user_problem_relations_on_user_id_and_problem_id", unique: true, using: :btree
+    t.index ["problem_id", "ranked_score"], name: "index_user_problem_relations_on_problem_id_and_ranked_score"
+    t.index ["user_id", "problem_id"], name: "index_user_problem_relations_on_user_id_and_problem_id", unique: true
   end
 
-  create_table "users", force: :cascade do |t|
-    t.string   "email",                  limit: 255, default: "",    null: false
-    t.string   "encrypted_password",     limit: 255, default: "",    null: false
-    t.string   "reset_password_token",   limit: 255
+  create_table "users", id: :serial, force: :cascade do |t|
+    t.string "email", limit: 255, default: "", null: false
+    t.string "encrypted_password", limit: 255, default: "", null: false
+    t.string "reset_password_token", limit: 255
     t.datetime "reset_password_sent_at"
     t.datetime "remember_created_at"
-    t.integer  "sign_in_count",                      default: 0
+    t.integer "sign_in_count", default: 0
     t.datetime "current_sign_in_at"
     t.datetime "last_sign_in_at"
-    t.string   "current_sign_in_ip",     limit: 255
-    t.string   "last_sign_in_ip",        limit: 255
+    t.string "current_sign_in_ip", limit: 255
+    t.string "last_sign_in_ip", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "brownie_points",                     default: 0
-    t.string   "name",                   limit: 255
-    t.string   "username",               limit: 255,                 null: false
-    t.boolean  "can_change_username",                default: false, null: false
-    t.string   "avatar",                 limit: 255
-    t.string   "confirmation_token",     limit: 255
+    t.integer "brownie_points", default: 0
+    t.string "name", limit: 255
+    t.string "username", limit: 255, null: false
+    t.boolean "can_change_username", default: false, null: false
+    t.string "avatar", limit: 255
+    t.string "confirmation_token", limit: 255
     t.datetime "confirmed_at"
     t.datetime "confirmation_sent_at"
-    t.string   "unconfirmed_email",      limit: 255
+    t.string "unconfirmed_email", limit: 255
     t.datetime "last_seen_at"
-    t.integer  "school_id"
-    t.string   "country_code",           limit: 3
-    t.date     "school_graduation"
-    t.index "lower((username)::text)", name: "index_users_on_username", unique: true, using: :btree
-    t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true, using: :btree
-    t.index ["email"], name: "index_users_on_email", unique: true, using: :btree
-    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true, using: :btree
+    t.integer "school_id"
+    t.string "country_code", limit: 3
+    t.date "school_graduation"
+    t.index "lower((username)::text)", name: "index_users_on_username", unique: true
+    t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true
+    t.index ["email"], name: "index_users_on_email", unique: true
+    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
 end