PHP Fatal error: Uncaught Error: Class “MyAppChat” not found in /var/www/html/bin/chat-server.php:12 [duplicate]

PHP Warning: Module “sockets” is already loaded in Unknown on line 0

PHP Fatal error: Uncaught Error: Class “MyAppChat” not found in /var/www/html/bin/chat-server.php:12

Stack trace:
#0 {main}
thrown in /var/www/html/bin/chat-server.php on line 12

Directory structure

 bin
    chat-server.php
 src
    chat.php
 vendor
 composer.json

My composer.json file:

{
    "autoload": {
        "psr-4": {
            "MyApp\": "src/"
        }
    },
    "require": {
        "cboden/ratchet": "^0.4.4"
    }
}