A quick overview of how this demo was made:
Make your rails app:
rails new myapp -m http://andreasronge.github.com/neo4j/rails.rb -O cd myapp/
Add to Gemfile:
gem 'devise-neo4j', :git => 'git://github.com/cfitz/devise-neo4j.git' gem 'omniauth' gem 'omniauth-facebook'
Now Update it and run Devise generator:
bundle update rails generate devise:install --orm=neo4j bundle exec rails g neo4j:devise User
Now pretty much follow the Devise guide found at github.com/plataformatec/devise/wiki/OmniAuth:-Overview :
Update the Routes to have devise_for Users. Update the User model to have the uid, name, and provider properties and make them attr_accessible. Add the find method to the User model. Look at the example in this app, since Neo4j.rb is slightly different than ActiveRecord. Add your FB app id and secret to the config/initializers/devise.rb
You should be able to run the application and go to localhost:3000/users/sign_in and see the log in with Facebook provider link.
Let me know if you have any questions or issues…