Replaces some hardwired variables with user-defined constants.

Connections/database_functions.php

@@ -1,5 +1,11 @@
 <?php
 require_once('YBDB.php');
+
+// User defined constants - read populate.sql for directions
+define("STORAGE_PERIOD", 14);
+define("ACCOUNTING_GROUP", "Sales");
+define("DEFAULT_TRANSACTION_TYPE", "Sale - Used Parts");
+define("DEFAULT_SHOP_USER", "Volunteer");
 
 //constants
 define("PAGE_START_SHOP", "/start_shop.php");