Merge foodcoop1040:order_message into master

Conflicts:
	plugins/messages/app/models/message.rb

app/models/order.rb

@@ -8,6 +8,7 @@ class Order < ActiveRecord::Base
   has_many :articles, :through => :order_articles
   has_many :group_orders, :dependent => :destroy
   has_many :ordergroups, :through => :group_orders
+  has_many :users_ordered, :through => :ordergroups, :source => :users
   has_one :invoice
   has_many :comments, -> { order('created_at') }, :class_name => "OrderComment"
   has_many :stock_changes