Add header comment; PSR-2 fixes; remove seeders

src/Http/RouterMiddleware.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Flarum\Http;
 
 use FastRoute\Dispatcher;