Reserved names for Web signup

    // check for duplicate user name
    if($username=="") {
        $output = webLoginAlert("Missing username. Please enter a user name.").$tpl;
        return;
    }

// MY Reserved signup
   elseif ($username=="array(
                        admin,
                        manager)"); {
                    $output=webLoginAlert("You cannot signup with this username!").$tpl;
                 return;
                }
                                        
// END MY Reserved signup

    else {
        $sql = "SELECT id FROM ".$modx->getFullTableName("web_users")." WHERE username='$username'";
        if(!$rs = $modx->db->query($sql)){
            $output = webLoginAlert("An error occured while attempting to retreive all users with username $username.").$tpl;
            return;
        } 
        $limit = $modx->db->getRecordCount($rs);
        if($limit>0) {
            $output = webLoginAlert("Username is already in use!").$tpl;
            return;
        }        
    }