[CRITICAL] Export DB button kills entire application

[therebelrobot]

Steps to reproduce:

1. Log in as admin
2. Go to Manage Brigade
3. Select Download DB Backup button at bottom of page

The request will fail, and if you go to the site outside of that, you'll get an application error

Relevant logs:

Jan 26 15:06:31 sfbrigade heroku/web.1:  State changed from up to crashed 
Jan 26 15:06:31 sfbrigade app/web.1:  /app/node_modules/mongodb-collection-dump/node_modules/mongodb/lib/mongodb/mongo_client.js:423 
Jan 26 15:06:31 sfbrigade app/web.1:                throw err 
Jan 26 15:06:31 sfbrigade app/web.1:                ^ 
Jan 26 15:06:31 sfbrigade app/web.1:  TypeError: Cannot read property 'collection' of null 
Jan 26 15:06:31 sfbrigade app/web.1:      at /app/node_modules/mongodb-collection-dump/index.js:26:24 
Jan 26 15:06:31 sfbrigade app/web.1:      at /app/node_modules/mongodb-collection-dump/node_modules/mongodb/lib/mongodb/mongo_client.js:420:15 
Jan 26 15:06:31 sfbrigade app/web.1:      at _combinedTickCallback (internal/process/next_tick.js:67:7) 
Jan 26 15:06:31 sfbrigade app/web.1:      at process._tickCallback (internal/process/next_tick.js:98:9) 
Jan 26 15:06:31 sfbrigade app/web.1:  make: *** [start] Error 1 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Linux 3.13.0-105-generic 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! argv "/app/.heroku/node/bin/node" "/app/.heroku/node/bin/npm" "start" 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! node v6.9.1 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! npm  v3.10.8 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! code ELIFECYCLE 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! brigadehub@0.1.2 start: `make start` 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Exit status 2 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR!  
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Failed at the brigadehub@0.1.2 start script 'make start'. 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Make sure you have the latest version of node.js and npm installed. 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! If you do, this is most likely a problem with the brigadehub package, 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! not with npm itself. 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Tell the author that this fails on your system: 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR!     make start 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! You can get information on how to open an issue for this project with: 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR!     npm bugs brigadehub 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Or if that isn't available, you can get their info via: 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR!     npm owner ls brigadehub 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! There is likely additional logging output above. 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR! Please include the following file with any support request: 
Jan 26 15:06:31 sfbrigade app/web.1:  npm ERR!     /app/npm-debug.log 
Jan 26 15:06:32 sfbrigade heroku/router:  sock=backend at=error code=H18 desc="Server Request Interrupted" method=GET path="/api/db/backup?token=[redacted]" host=codeforsanfrancisco.org request_id=[redacted] fwd="[redacted]" dyno=web.1 connect=0ms service=521ms status=503 bytes= 
Jan 26 15:06:32 sfbrigade heroku/web.1:  Process exited with status 1 

[therebelrobot]

This looks to be an issue with how mongodb-collection-dump is interacting with the heroku environment, I can't replicate with the same dataset locally... :/ Looking into this further

[therebelrobot]

Failing line: https://github.com/nickpoorman/mongodb-collection-dump/blob/master/index.js#L26