Merge pull request railsbridge#568 from nearbycoder/master

Added `gem install bundler` within the instructions

Author: tjgrathwell

sites/en/installfest/deploy_a_rails_app.step

@@ -87,6 +87,7 @@ step "Deploy your app to Heroku" do
     end
 
     console <<-BASH
+gem install bundler
 bundle install --without production
     BASH