Dokku and Silex

composer.json

{
    "require": {
        "silex/silex": "~1.1"
    },
    "extra": {
        "heroku": {
            "framework":        "silex",
            "document-root":    "web",
            "index-document":   "index.php"
        }
    }
}

index.php

<?php
// web/index.php

use Symfony\Component\HttpFoundation\Request;

require_once __DIR__.'/../vendor/autoload.php';

$app = new Silex\Application();

$app->get('/', function (Request $request) use ($app) {
	return $request->server->get("HTTP_X_FORWARDED_FOR");
});

$app->run();