Fix some coding style issues

classes/userkey_manager_interface.php

@@ -1,14 +1,34 @@
 <?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
 /**
- * Created by PhpStorm.
- * User: dmitriim
- * Date: 16/08/2016
- * Time: 15:23
+ * Key manager interface.
+ *
+ * @package    auth_userkey
+ * @copyright  2016 Dmitrii Metelkin (dmitriim@catalyst-au.net)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
 namespace auth_userkey;
 
-
+/**
+ * Interface userkey_manager_interface describes key manager behaviour.
+ *
+ * @package auth_userkey
+ */
 interface userkey_manager_interface {
     /**
      * Create a user key.