add auto take cash function

app/models/order_detail.rb

@@ -3,7 +3,9 @@ class OrderDetail < ActiveRecord::Base
   has_paper_trail
   self.table_name = "order_details"
   belongs_to :product
-  belongs_to :order, :foreign_key => :order_id
+  #belongs_to :order, :foreign_key => :order_id
+  has_one :order, :foreign_key=>:order_id, :primary_key=>:order_id
+
 
   def order_state
     order = Order.where("id = ?", self.order_id).first