diff --git a/Gemfile b/Gemfile
old mode 100755
new mode 100644
index 4e2bfcb..9e39988
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'nested_form', '~> 0.3.2'
 # Use mysql as the database for Active Record
 gem 'mysql2'
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
old mode 100755
new mode 100644
index 2896291..b204152
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -102,7 +102,9 @@ GEM
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
@@ -123,7 +125,8 @@ GEM
       jquery-rails
       paperclip (>= 3.4)
       rails (>= 3.1)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.5)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -230,7 +233,7 @@ DEPENDENCIES
   nested_form (~> 0.3.2)
   paperclip (~> 5.1)
   papercrop (~> 0.3.0)
-  puma (~> 3.0)
+  puma (~> 4.3)
   rails (~> 5.2, >= 5.2.1)
   redis (~> 3.0)
   russian (~> 0.6.0)