/**
* when user login in backend , it should be 'Administrator' or ,'Merchant'
*/
public static function beforeLogin()
{
Event::on(\yii\web\User::className(), \yii\web\User::EVENT_BEFORE_LOGIN, function ($event) {
$user = $event->identity;
$auth = new DbManager();
$auth->init();
$role = $auth->getRolesByUser($user->id);
$event->isValid = in_array(current($role)->name, ['Administrator', 'Merchant']);
});
}