Add plugin shell.

src/Shell/PluginShell.php

@@ -0,0 +1,25 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link          http://cakephp.org CakePHP(tm) Project
+ * @since         3.0.0
+ * @license       http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Shell;
+
+use Cake\Console\Shell;
+
+/**
+ * Shell for tasks related to plugins.
+ *
+ */
+class PluginShell extends Shell
+{
+}

tests/TestCase/Shell/CompletionShellTest.php

@@ -120,7 +120,7 @@ class CompletionShellTest extends TestCase
         $output = $this->out->output;
 
         $expected = "TestPlugin.example TestPlugin.sample " .
-            "TestPluginTwo.example TestPluginTwo.welcome i18n orm_cache plugin_assets server sample\n";
+            "TestPluginTwo.example TestPluginTwo.welcome i18n orm_cache plugin_assets plugin server sample\n";
         $this->assertTextEquals($expected, $output);
     }