fix first bill amount less than actual sales

app/models/order.rb

@@ -8,6 +8,8 @@ class Order < ApplicationRecord
   belongs_to :customer
   has_many :order_items, autosave: true , inverse_of: :order
   has_many :assigned_order_items
+  has_one :booking_order
+  has_one :booking, through: :booking_order
 
   #internal references attributes for business logic control
   attr_accessor :items, :guest, :table_id, :new_booking, :booking_type, :employee_name, :booking_id, :extra_time, :is_extra_time