add Plugin class for BC

Author: steinkel

src/Plugin.php

@@ -0,0 +1,21 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Copyright 2010 - 2019, Cake Development Corporation (https://www.cakedc.com)
+ *
+ * Licensed under The MIT License
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright Copyright 2010 - 2018, Cake Development Corporation (https://www.cakedc.com)
+ * @license MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+
+namespace CakeDC\Users;
+
+/**
+ * Plugin class for backward compatibility.
+ */
+class Plugin extends UsersPlugin
+{
+}