Create new Plugin for Mautic

I am working on a repository based on the Mautic repository.
I just created a test plugin called "HelloWorldBUndle", however, it does not appear in the list of Plugins available on the page:

This is the layout of the folders and files:

This is the "HelloWorldBundle.php" file

<?php
// plugins/HelloWorldBundle/HelloWorldBundle.php

namespace MauticPlugin\HelloWorldBundle;

use Mautic\PluginBundle\Bundle\PluginBundleBase;

class HelloWorldBundle extends PluginBundleBase
{
    // Nothing more required
}

And this is the "config.php"

<?php
// plugins/HelloWorldBundle/Config/config.php

return array(
    'name'        => 'Hello World',
    'description' => 'This is an example config file for a simple Hellow World plugin.',
    'author'      => 'Marty Mautibot',
    'version'     => '1.0.0',