Was tracking along my journey of learning Ruby on Rails (which is an excellent tool), but the getting started guide isn’t always easy to follow. For once suddenly I encountered a problem above which caused by a bug on the sample code.
After spending half an hour or so I figured out the getting started guide was version controller on their git repository. You can clone the rails repository using git clone https://github.com/rails/rails.git. The getting started guide is located at guides/source/getting_started.md
Also interestingly, someone has fixed the bug I saw on the git HEAD. So the next time you had problem with the tutorial, one thing to try is check the latest tutorial version on git: https://github.com/rails/rails/blob/master/guides/source/getting_started.md
And ofcourse if you spot another bug you should contribute the fix by submitting a pull request :).