设置size_id默认值

app/models/product.rb

@@ -23,6 +23,12 @@ class Product < ActiveRecord::Base
         if self.show_flag
             self.relate_product_id = self.id
         end
+        if self.size_id.nil?
+            self.size_id = 0
+        end
+        if self.color_id.nil?
+            self.color_id = 0
+        end
     end
 
     def del_picture