Add revised_amount to snapshot

db/migrate/1_create_shotengai_products_and_orders.rb

@@ -62,6 +62,9 @@ class CreateShotengaiProductsAndOrders < ActiveRecord::Migration[5.1]
     create_table :shotengai_snapshots do |t|
       t.decimal :original_price, precision: 9, scale: 2
       t.decimal :price, precision: 9, scale: 2
+      # Merchant can change the amount of snapshot
+      t.decimal :revised_amount, precision: 9, scale: 2
+         
       t.integer :count
       t.json :spec 
       t.json :banners

lib/shotengai/snapshot.rb

@@ -6,6 +6,7 @@ module Shotengai
   #  id                  :integer          not null, primary key
   #  original_price      :decimal(9, 2)
   #  price               :decimal(9, 2)
+  #  revised_amount      :decimal(9, 2)
   #  count               :integer
   #  spec                :json
   #  banners             :json

spec/factories/shotengai_snapshots.rb

@@ -5,6 +5,7 @@
 #  id                  :integer          not null, primary key
 #  original_price      :decimal(9, 2)
 #  price               :decimal(9, 2)
+#  revised_amount      :decimal(9, 2)
 #  count               :integer
 #  spec                :json
 #  banners             :json