public static function getUserRole()
 {
     //role to user type mapping can be done using db table too. currently its written here in roleMap array
     if (Yii::app()->user->isGuest) {
         return false;
     }
     $userType = AppCommon::getUserType();
     if ($userType !== false) {
         $roleMap = array("0" => "customer", "1" => "seller", "2" => "moderator", "3" => "administrator");
         return $roleMap[$userType];
     } else {
         return false;
     }
 }