add balance promotion shop promotion

app/models/promotion.rb

@@ -1,7 +1,7 @@
 class Promotion < ActiveRecord::Base
     has_paper_trail
     self.table_name = "promotions"
-    validates :begin_time,:end_time,:name,:order_type, presence: true
+    validates :begin_time,:end_time,:name,:order_type,:depart_record, presence: true
     has_and_belongs_to_many :depart_record
 
     def prodcut1