<?php

namespace Ares\CustomModule\Controller;

use Ares\Framework\Controller\BaseController;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;

/**
 * Class Controller
 *
 * @package Ares\CustomModule\Controller
 */
class Controller extends BaseController
{
    /**
     * Reveals a custom response to the user
     *
     * @param Request  $request  The current incoming Request
     * @param Response $response The current Response
     *
     * @return Response Returns a Response with the given Data
     */
    public function customResponse(Request $request, Response $response): Response
    {
        /** @var string $customResponse */
        $customResponse = 'your custom response';

        return $this->respond(
            $response,
            response()
                ->setData($customResponse)
        );
    }
}

return function (App $app) {
    // Registers our custom routes that calls the customResponse function in our custom controller
    $app->get('/custom', \Ares\CustomModule\Controller\Controller::class . ':customResponse');
};

<?php

namespace Ares\CustomModule\Provider;

use Ares\CustomModule\Model\Custom;
use League\Container\ServiceProvider\AbstractServiceProvider;

/**
 * Class CustomServiceProvider
 *
 * @package Ares\CustomModule\Provider
 */
class CustomServiceProvider extends AbstractServiceProvider
{
    /**
     * @var array
     */
    protected $provides = [
        Custom::class
    ];

    /**
     * Registers new service.
     */
    public function register()
    {
        $container = $this->getContainer();

        $container->add(Custom::class, function () {
            return new Custom();
        });
    }
}

    // Adds our CustomProvider to add Customs
    $container->addServiceProvider(
        new \Ares\CustomModule\Provider\CustomServiceProvider()
    );