Enh: Auto create a migration for every action CRUD yii\rbac\Item

[githubjeka]

The file is like as

<?php

use yii\db\Schema;
use yii\db\Migration;

class m150910_204507_init_blog_rbac extends Migration
{
    public function up()
    {
        $auth = Yii::$app->authManager;

        $manageBlog = $auth->createPermission('manageBlog');
        $manageBlog->description = 'Manage blog';
        $auth->add($manageBlog);

        $admin = $auth->createRole('admin');
        $admin->description = 'Administrator';
        $auth->add($admin);
        $auth->addChild($admin, $manageBlog);
    }

    public function down()
    {
        Yii::$app->authManager->removeAll();
    }
}