This is essentially a default Rails 3 app with some extras added off the bat. The Gemfile has been changed to use HAML, Mongoid, as well as Twitter Bootstrap. I have also run the installation commands for Mongoid and Bootstrap.
I prefer Mongoid and HAML to the Rails defaults, so this is an example of how to integrate these tools from a blank Rails 3 app. From here, it’s just a little easier to make beautiful, powerful Rails apps.