Exec. delete

exam/classes/Models/User/User.php

@@ -612,6 +612,7 @@ class User implements JsonSerializable
     $db = Database::getInstance();
     $stmt = $db->prepare("DELETE FROM egb_benutzer WHERE id = :ID");
     $stmt->bindValue(":ID", $this->id);
+    $stmt->execute();
 
     $stmt = $db->prepare(
       "SELECT