Add rake to Gemfile.
Add rake to Gemfile.

This seems weird, but its required for Travis.

envato/rake,envato/rake,Vanzct/rake,utilum/rake,esasse/rake,jaustinhughey/rake,bentley/rake,pjump/rake,codedogfish/rake,88rabbit/rake,askl56/rake,ruby/rake,taiganakagawa/rake,ipmobiletech/rake,tmornini/rake,hsbt/rake,ruby/rake,hsbt/rake,zzak/rake