This simple app is an early attempt at getting DCI features into Rails and working towards some common conventions. I by no means expect to have every case covered here or every convention perfect at this time; this is a set of practices and conventions we're looking to grow over time as a community.
I've written up a set of walkthroughs and discussions on the project at the developerWorks website. I'll continue to add materials as the project matures and evolves.
If all's well when you run the app, you should see "I performed work." appear. Note that the User class doesn't have this behavior defined, only the AdminRole module does. A new instance of User that doesn't have the 'admin' role applied won't have this behavior available.