Switch into the hasfriends
repository and run the following:
gem install bundler
gem install git_remote_branch
gem install zeus
gem install powder
rbenv rehash
git checkout master
git pull origin master
bundle
If you're using Pow (which you should be on this app):
powder respawn
You only need to do all this once.
If this version of Ruby was previously installed, you'll need to reinstall with these steps.