fixed first bill with discount

app/models/sale_item.rb

@@ -100,7 +100,7 @@ class SaleItem < ApplicationRecord
       discount_account = {:name => a.title, :price => 0}
 
       # Check for actual sale items
-      sale_items.where("status = 'Discount'").find_each do |si|
+      sale_items.where("status = 'Discount'").each do |si|
         if si.account_id == a.id
           discount_account[:price] = (discount_account[:price].abs + si.price.abs) * (1)
         end