*Edge*

* ActiveModel::Observer#add_observer!

  It has a custom hook to define after_find that should really be in a
  ActiveRecord::Observer subclass:

	  def add_observer!(klass)
	    klass.add_observer(self)
	    klass.class_eval 'def after_find() end' unless
				klass.respond_to?(:after_find)
	  end

* Change the ActiveModel::Base.include_root_in_json default to true for Rails 3 [DHH]

* Add validates_format_of :without => /regexp/ option. #430 [Elliot Winkler, Peer Allan]

  Example :

      validates_format_of :subdomain, :without => /www|admin|mail/

* Introduce validates_with to encapsulate attribute validations in a class.  #2630 [Jeff Dean]

* Extracted from Active Record and Active Resource.