Add option to show total discounts on receipt

database/database.sql

@@ -66,7 +66,8 @@ INSERT INTO `ospos_app_config` (`key`, `value`) VALUES
 ('print_bottom_margin', '0'),
 ('print_right_margin', '0'),
 ('default_sales_discount', '0'),
-('lines_per_page', '25');
+('lines_per_page', '25'),
+('show_total_discount', '1');
 
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