change ordr reservation api

db/migrate/20180406080240_create_order_reservations.rb

@@ -6,6 +6,7 @@ class CreateOrderReservations < ActiveRecord::Migration[5.1]
     	t.string 	   :customer_id, :null => false
     	t.datetime 	 :requested_time, :null => false
       t.string     :callback_url, :null => false
+      t.string     :transaction_ref, :null => false
     	t.integer :item_count, :null => false, :default => 0
       t.integer :total_customer
     	t.string 	:payment_type
@@ -18,6 +19,7 @@ class CreateOrderReservations < ActiveRecord::Migration[5.1]
     	t.string 	:status, :null => false, :default => "new"
       t.string  :order_remark
       t.string  :reservation_remark
+      t.timestamps
     end
   end
 

db/migrate/20180406080359_create_order_reservation_items.rb

@@ -16,6 +16,7 @@ class CreateOrderReservationItems < ActiveRecord::Migration[5.1]
 		t.string :remark
 		t.string :options
 		t.boolean :taxable, :null => false, :default => true
+		t.timestamps
     end
   end
 

db/migrate/20180406080436_create_deliveries.rb

@@ -9,6 +9,7 @@ class CreateDeliveries < ActiveRecord::Migration[5.1]
     	t.string :direction_address
     	t.string :delivery_fee
     	t.string :remark
+      t.timestamps
     end
   end