Some missing docs

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@369 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,17 @@
 *SVN*
 
+* Added that Observers can use the observes class method instead of overwriting self.observed_class().
+
+    Before:
+      class ListSweeper < ActiveRecord::Base
+        def self.observed_class() [ List, Item ]
+      end
+    
+    After:
+      class ListSweeper < ActiveRecord::Base
+        observes List, Item
+      end
+
 * Fixed that conditions in has_many and has_and_belongs_to_many should be interpolated just like the finder_sql is
 
 * Fixed Base#update_attribute to be indifferent to whether a string or symbol is used to describe the name