Replace float with Decimal for price calculations

Fix Decimal precision issue

Fix Decimal precision issue

Fix Decimal precision issue

Fix old prices for tickets

Fix Decimal precision issue

sql/create_database.sql

@@ -28,7 +28,7 @@ CREATE TABLE `catering_menu_items` (
   `catering_menu_item_id` int(11) NOT NULL AUTO_INCREMENT,
   `name` varchar(45) NOT NULL,
   `additional_info` varchar(300) DEFAULT '',
-  `price` int(11) NOT NULL DEFAULT 0,
+  `price` varchar(45) NOT NULL DEFAULT '0',
   `category` varchar(80) NOT NULL,
   `is_disabled` tinyint(4) DEFAULT 0,
   PRIMARY KEY (`catering_menu_item_id`)