private static function populateList($db)
 {
     $userQuery = "SELECT user FROM auth";
     $userQuery = $db->real_escape_string($userQuery);
     $userResult = $db->query($userQuery);
     self::$_userList = array();
     while ($row = $userResult->fetch_array()) {
         self::$_userList[] = $row[0];
     }
 }