add route group

[wpjscc]

can use addGroup

       $app->addGroup('/users', [
            // middleware1,
            // middleware2
        ], function ($app) {
            $app->get('/{name}', function ($request) {
                return \React\Http\Message\Response::plaintext(
                    "Hello " . $request->getAttribute('name') . "!\n"
                );
            });
            $app->addGroup('/{name}/posts', [
                // middleware1,
                // middleware2
            ], function ($app) {
                $app->get('/{post}', function ($request) {
                    return \React\Http\Message\Response::plaintext(
                        "Hello User {$request->getAttribute('name')} Posts " . $request->getAttribute('post') . "!\n"
                    );
                });
            });
        });

        $app->addGroup('/posts', [
            // middleware1,
            // middleware2
        ], function ($app) {
            $app->get('/{post}', function ($request) {
                return \React\Http\Message\Response::plaintext(
                    "Hello Posts " . $request->getAttribute('post') . "!\n"
                );
            });
        });

[SimonFrings]

Follow up pull request in #241.