Fix API requests to Foursquare

“As of July 1, 2014, versions that are earlier than 20120609 are officially
unsupported, and requests sent with them will be summarily rejected.”

https://developer.foursquare.com/overview/versioning
Switch to Ruby 2.1.3, Unicorn
gitignore
Merge pull request #2 from mislav/fix-api

Fix API request, upgrade Ruby, Rails & Unicorn