title: Dockerfile and yml configuration
body: <p>I use docker (with nginx - docker-nginx-php-mysql) as the environment to run PHP applications.
  I'm trying to add websocket to my application and have some difficulties in configure to Dockerfileand docker-compose.yml</p>
  
  <p>I have server file in cmd.php (location: docker-nginx-php-mysql\www\ratchet_chatapp\cmd.php):</p>
  
  <pre><code>&lt;?php
  require 'vendor/autoload.php';
  
  use Ratchet\Server\IoServer;
  use Ratchet\Http\HttpServer;
  use Ratchet\WebSocket\WsServer;
  use ChatApp\Chat;
  
  $server = IoServer::factory(
      new HttpServer(
          new WsServer(
              new Chat()
          )
      ),
      8090
  );
  
  $server-&gt;run();
  </code></pre>
  
  <p>I use the connection to open the web socket on main.js (location: docker-nginx-php-mysql\www\ratchet_chatapp\js\main.js) with:</p>
  
  <pre><code>var conn = new WebSocket('ws://localhost:8090');
      conn.onopen = function(e) {
          console.log("Connection established!");
      };
  </code></pre>
  
  <p>my Dockerfile (location: docker-nginx-php-mysql\php\Dockerfile):</p>
  
  <pre><code>FROM php:7.3-fpm
  
  RUN apt-get update &amp;&amp; apt-get install -y libzip-dev libpng-dev git zip unzip libgd3 libgd-tools  libxml2 libxml2-dev mariadb-client &amp;&amp; docker-php-ext-install pdo_mysql  mysqli gd soap zip
  </code></pre>
  
  <p>my docker-compose.yml (location: docker-nginx-php-mysql):</p>
  
  <pre><code>version: "3"
  
  services:
    nginx:
      build: ./nginx/
      ports:
          - 80:80
      links:
          - php
      volumes:
          - ./www:/var/www/html 
      networks:
          uln:
           ipv4_address: 10.6.0.2
  
    php:
      build: ./php/
      expose:
          - 9000
          - 8090
      links:
          - mysql
      volumes:
          - ./www:/var/www/html 
      networks:
          uln:
           ipv4_address: 10.6.0.3
  
    app:
      image: php:7.3-fpm
      volumes:
          - ./www:/var/www/html
      command: "true"
  
    mysql:
      image: mysql:5.7
      ports:
          - 3306:3306
      volumes:
          - ./mysql:/var/lib/mysql
      environment:
          MYSQL_ROOT_PASSWORD: secret
          MYSQL_DATABASE: webprog 
          MYSQL_USER: webprog 
          MYSQL_PASSWORD: webprog
      networks:
          uln:
           ipv4_address: 10.6.0.4
  
    phpmyadmin:
      image: phpmyadmin/phpmyadmin
      ports:
          - 8080:80
      links:
          - mysql
      environment:
          PMA_HOST: mysql
      networks:
          uln:
           ipv4_address: 10.6.0.5
  
  networks:
      uln:
       ipam:
          config:
           - subnet: 10.6.0.0/16
  </code></pre>
  
  <p>I tried to configure the Dockerfile with EXPOSE 8090 and add it to the yml but still doesn't work.
  How can I change the Dockerfile and the yml properly?</p>
  
  <p>Thanks!</p>