added the ability to set the sort order for roles

git-svn-id: http://redmine.rubyforge.org/svn/trunk@208 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/role.rb

@@ -20,6 +20,7 @@ class Role < ActiveRecord::Base
   has_and_belongs_to_many :permissions
   has_many :workflows, :dependent => :delete_all
   has_many :members
+  acts_as_list
 
   validates_presence_of :name
   validates_uniqueness_of :name