Interface 'Ratchet\MessageComponentInterface' not found
Hello,

I've referred [http://socketo.me/docs/hello-world](http://socketo.me/docs/hello-world) example,
directory structure > bin/chat-server.php, src/MyApp/Chat.php still shows 'Ratchet\MessageComponentInterface' not found

Note: - Tried composer update, as well ` "autoload": {
        "psr-4": {
            "MyApp\\": "src"
        }
    }`