Update changelog

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2012 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Make destroy return self #1913 [sebastian.kanthak@muehlheim.de]
+
 * Fix typo in validations documentation #1938 [court3nay]
 
 * Make acts_as_list work for insert_at(1) #1966 [hensleyl@papermountain.org]