Heroku removed the need for it with Rails 5

wassimk · wassimk · commit 911fb31be089 · 2016-08-24T15:31:31.000-05:00
https://devcenter.heroku.com/articles/getting-started-with-rails5#heroku-gems Closes #569
diff --git a/sites/en/installfest/deploy_a_rails_app.step b/sites/en/installfest/deploy_a_rails_app.step
@@ -73,7 +73,6 @@ step "Deploy your app to Heroku" do
 
       group :production do
         gem 'pg'
-        gem 'rails_12factor'
       end
     RUBY
 
diff --git a/sites/en/intro-to-rails/_deploying_to_heroku.step b/sites/en/intro-to-rails/_deploying_to_heroku.step
@@ -23,7 +23,6 @@ end
 
 group :production do
   gem 'pg'
-  gem 'rails_12factor'
 end
   RUBY
 end
