Maybe Heroku changed something, or maybe it's the new Cedar stack, but using private gems from Github is pretty easy. It apparently didn't work before. The important part is in your ~/.ssh/config Host heroku.com ForwardAgent yes After that it's no big deal. Just use an ssh URL to Github (or wherever, the Github part doesn't really matter) in your Gemfile and off you go! source :rubygems ruby '1.9.3' gem 'sinatra', :git => 'git@github.com:darkhel…