remove custom solution to visually show that you are running in development 
environment and replace with rack-dev-mark gem
move rack-dev-mark gem to development group
Merge pull request #1691 from TracksApp/dev-mark

remove custom solution to visually show that you are running in developm...
fix lint warnings for tracks.js - first pass

found on codeclimate. this is the first pass
fix lint warnings for tracks.js - first pass

found on codeclimate. this is the first pass
fix lint warnings for tracks.js - third pass

found on codeclimate. this is the third pass
fix lint warnings for tracks.js - fourth pass

found on codeclimate. this is the fourth pass
remove duplication in tracks.js
Update Rails to 4.1.2
Update Rails to 4.1.2