Adding rubocop gem to check for logical and style problems

## Assigned directories
* app/helpers and app/views - daviddavis
* app/controllers/api - adam
* app/models - eric

## Directories we're checking as of now
* lib
* script
* db
* config

## Directories left to do
* app/helpers
* app/views
* app/controllers
* spec
* test
* integration_spec
* engines