Topic: HOWTO: Tutorial and Example App for Rails 3 + Mongoid + Devise
I've put together an example application that demonstrates Mongoid and Devise working together on Rails 3.
Mongoid is for data storage (alternative to SQL databases). Devise is for authentication (alternative to RESTful authentication or Authlogic).
It's on GitHub:
There's a step-by-step tutorial on the wiki that shows how to build it.
There's also an application template generator so anyone can use the example as a beginning point for a new Rails app.
Right now (24 June 2010) it requires:
* ruby (version 1.8.7 or 1.9.2)
* rails (version 3.0.0.beta4)
* mongoid (version 2.0.0.beta7)
* bson_ext (version 1.0.1)
* devise (version 1.1.rc2)
There are options to use Haml and Heroku as well.