3.php

<?php
// portal/src/Symfony 
# could have been portal/src/Portal/Common/Infrastructure/Symfony but I got lazy
namespace Portal\Common\Infrastructure\Symfony;

use Portal\Common\Infrastructure\Symfony\DependencyInjection\AppContextExtension;
use Symfony\Component\HttpKernel\Bundle\Bundle;

# I suppose SymfonyBundle might be a better name 
class PortalBundle extends Bundle
{
    public function getContainerExtension()
    {
        return new AppContextExtension();
    }
}