Hi I have started learning RoR recently and had like hundreds on hundreds of problems installing it on MAC. Finally I have everything installed: Ruby Ruby Gems Rails Git Heroku Now I am following the following tutoria from chapter 2: http://ruby.railstutorial.org/chapters/a-demo-app#top And when it comes to the part to construct the data model it comes up with the following error: Artful-Dodgers-iMac:~ mohammedshuheb$ cd ~/rails_projects Artful-Dodgers-iMac:rails_projects mohammedshuheb$ cd demo_app Artful-Dodgers-iMac:demo_app mohammedshuheb$ rails generate scaffold Users name:string email:string /Users/mohammedshuheb/rails_projects/demo_app/config/application.rb:7: undefined method `groups' for Rails:Module (NoMethodError) from /Library/Ruby/Gems/1.8/gems/railties-3.0.11/lib/rails/commands.rb:15:in `require' from /Library/Ruby/Gems/1.8/gems/railties-3.0.11/lib/rails/commands.rb:15 from script/rails:6:in `require' from script/rails:6 I used the command: rails generate scaffold Users name:string email:string to make the two fields name and email. Anyone? Need help Thanks!!!