ZMQ not transmitting data to websocket
I followed the steps on http://socketo.me/docs/push but couldn't reproduce the functionality. I tried a very basic example, but the Websocket function is not called - I want to echo the received data, but the function is never called. 

First I implemented the **Pusher**: 

``` php
namespace App\WebSocket;
class Pusher implements WampServerInterface {
    // empty functions for the interface

    // call this, when ZMQ sends data.
    public function onEvent($data) {
        echo $data . "\n";
    }
}
```

This is the **post action handler**.

``` php
// $data is a json encoded database record.
$context = new \ZMQContext();
$socket  = $context->getSocket(\ZMQ::SOCKET_PUSH, 'websocket');
$socket->connect('tcp://127.0.0.1:5555');

echo $data . "\n";
$socket->send($data);
```

And this is what I do to initialise the **websocket**.

``` php
// WebSocket/ZMQ startup
$loop   = Factory::create();
$pusher = new \App\WebSocket\Pusher;

$context = new Context($loop);
$pull    = $context->getSocket(\ZMQ::SOCKET_PULL);
$pull->bind('tcp://127.0.0.1:5555');
$pull->on('message', [$pusher, 'onEvent']);

$websocket = new Server($loop);
$websocket->listen(8080, '0.0.0.0');

$webServer = new IoServer(
    new HttpServer(
        new WsServer(
            new WampServer(
                $pusher
            )
        )
    ),
    $websocket
);

$loop->run();
```

The websocket is running, the server event works too...
