Added omniauth-facebook gem
	modified:   Gemfile

Changed google_user to be provider_user since we can now use facebook as well
	modified:   app/controllers/session_controller.rb

Added method self.from_omniauth(auth) which adds oauth_token and oauth_expires_at to user
Updated self.find_or_create_user_by_uid(auth) to reflect the new method.
	modified:   app/models/user.rb

Added a link to login with facebook
	modified:   app/views/users/_login.html.erb

Added facebook as a provider, along with our key and secret
  modified:   config/initializers/omniauth.rb

Added a facebook callback route to match to sessions#create
	modified:   config/routes.rb

Added oauth_token and expires_at columns to the user table
	new file:   db/migrate/20130608230829_add_more_oauth_columns_to_user.rb

Added tests for logging in with facebook.
	modified:   spec/features/user_spec.rb

Added a mock and stub to test logging in with facebook
	modified:   spec/support/omniauth_helper.rb
removed create_with_omniauth method that is no longer being used. (Replaced with self.from_omniauth(auth))
Merge branch 'master' into facebook
Added new method to display error messages for comments, using js.
modified:   app/assets/javascripts/comment.js
modified:   app/controllers/comments_controller.rb
modified:   app/views/comments/_form.html.erb
modified:   spec/features/comments_spec.rb
Merge branch 'master' of https://github.com/thomasstephane/eventoverflow