[skip] Made typical adjustments to a new Rails application (20m)

 * Removed `turbolinks`
 * Added `bootstrap` script
 * Uses `unicorn` as the web server
 * Added `spring` and `letter_opener` and `pry` to boost productivity during development
 * Configured for use with Jenkins
 * Configured for use with Errbit
[feature] Added Devise for authentication (10m)
[improvement] Added Twitter Bootstrap and Font Awesome (15m)
[feature] Added the concepts of Skills and Stats and styled the display of them (1.5h)
[skip] Added Tester Bar in development environment (5m)
[feature] Added the ability to assess teammates (1.5h)
[skip] Deleted /concerns folders (1m)
[improvement] Increased the click target of the slider track (1m)
[skip] Displayed logged-in user's name in the navbar (1m)
[improvement] Added rank badge next to each score (15m)
[improvement] Touched up styling of home page (20m)
[improvement] Added rank badges to the Assessment form (15m)