Alerts: replace 'error' class with 'danger'

models/Dispatcher.php

@@ -50,7 +50,7 @@ class Dispatcher
 	public static function kickGuest($title = null, $message = null)
 	{
 		$form = new LogInForm('Log in');
-		$form->adopt(new Alert($title ?? '', $message ?? 'You need to be logged in to view this page.', 'error'));
+		$form->adopt(new Alert($title ?? '', $message ?? 'You need to be logged in to view this page.', 'danger'));
 		$form->setRedirectUrl($_SERVER['REQUEST_URI']);
 
 		$page = new MainTemplate('Login required');