diff --git a/upload/system/library/cart/user.php b/upload/system/library/cart/user.php
index 769a64237f2..3c17df5ae86 100644
--- a/upload/system/library/cart/user.php
+++ b/upload/system/library/cart/user.php
@@ -2,6 +2,7 @@
 namespace Cart;
 class User {
 	private $user_id;
+	private $user_group_id;
 	private $username;
 	private $permission = array();