Use memcache within Ratchet

as the title states how can i use memcache in Ratchet websockets.

I isntalled memcache and valided that is is active with php -l

memcache

memcache support => enabled
Version => 4.0.5.2
Revision => $Revision$

I followed a lot of guides (which is a challenge as there is memcache and memcached and Google does mix the two often).

When i follow the official guide and also a lot of stackoverflow posts: nr1, nr2 and number 3 for example.

I think everything is correctly installed, but when i start my server (which starts ratchet and memcache) i get this error:
PHP Fatal error: Uncaught Error: Class “SessionProvider” not found in /var/www/project/websocket/bin/chat-server.php:16

My file looks like:

use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;
use MyAppChat;
use SymfonyComponentHttpFoundationSessionSession;
use SymfonyComponentHttpFoundationSessionStorageNativeSessionStorage;
use SymfonyComponentHttpFoundationSessionStorageHandlerMemcacheSessionHandler;
use SymfonyComponentHttpFoundationSessionStorageHandler;

require dirname(__DIR__) . '/vendor/autoload.php';

$memcache = new Memcache;
$memcache->connect('localhost', 11211);

$session = new SessionProvider(
    new MyApp
  , new HandlerMemcacheSessionHandler($memcache)
);

$server = IoServer::factory(
    new HttpServer(
        new WsServer(
            new Chat()
        )
    ),
    8080
);
echo("Server Running on 8080n-----------------n");
$server->run();

The structure of my folders is correct as far as i can see.
i’m not sure if and what to add to my composer file, as i cant find anything about it.

{
"autoload": {
    "psr-4": {
        "MyApp\": "src"
    }
},
"require": {
    "cboden/ratchet": "^0.4"
}

My goal is simply to share sessions between PHP/webserver and Ratchet to use them.