Rails 4 has deprecated :order in has_many to use a lambda instead, update the guide accordingly

guides/source/active_record_querying.md

@@ -732,7 +732,7 @@ The `reorder` method overrides the default scope order. For example:
 class Post < ActiveRecord::Base
   ..
   ..
-  has_many :comments, order: 'posted_at DESC'
+  has_many :comments, -> { order('posted_at DESC') }
 end
 
 Post.find(10).comments.reorder('name')