diff --git a/api/upgrade.php b/api/upgrade.php
index dcbcb67..c7ca7ec 100644
--- a/api/upgrade.php
+++ b/api/upgrade.php
@@ -131,8 +131,11 @@ if(isset($input->action) && $input->action == "requestUpgrade") {
     }
     if($currentVersion < 4) {
         $sql["mysql"] = "
+            ALTER TABLE permissions DROP FOREIGN KEY permissions_ibfk_2;
             RENAME TABLE user TO users;
             ALTER TABLE permissions CHANGE user userid INT(11);
+            ALTER TABLE permissions
+              ADD CONSTRAINT permissions_ibfk_2 FOREIGN KEY (userid) REFERENCES users (id) ON DELETE CASCADE;
             
             ALTER TABLE users ADD CONSTRAINT UNIQUE KEY user_name_index (name);