Remove gemfile.lock 
Remove gemfile.lock 

Using OS X gems causes Heroku to choke when you 
use `Gemfile.lock` file, because the lock files
are specific to a given system. The solution is
to remove the `.lock` file once again

http://stackoverflow.com/questi
ons/5958294/git-push-heroku-failing-because-trying-to-install-development-gems-bundle-withou/6162278#6162278
AMEE/amee-location-footprinter,AMEE/amee-location-footprinter