title: Docker app fails to launch with shinyproxy in docker-compose, works with run
body: <p>I have a shinyproxy app that works fine with <code>docker run ...</code></p>
  
  <pre><code>docker run --name=shinyproxy -d -v /var/run/docker.sock:/var/run/docker.sock --net telethonkids-net -p 80:8080 --rm telethonkids/shinyproxy
  </code></pre>
  
  <p>by when I try the following docker-compose shinyproxy loads on the browser, but the app times out when trying to start (Container unresponsive):</p>
  
  <pre><code>version: "3.6"
  services:
      shinyproxy:
        build:
          context: ./shinyproxy
          dockerfile: Dockerfile
        networks:
          - telethonkids-net
        volumes:
          - "/var/run/docker.sock:/var/run/docker.sock"
        ports:
          - 80:8080
  
  networks:
    telethonkids-net:
  </code></pre>
  
  <p>I'm running this on a Ubuntu 18.04 virtual box. There are a few other questions with similar titles, but none that I saw that matched my problem.</p>
  
  <p>Here's my application.yaml</p>
  
  <pre><code>proxy:
    title: Shiny Proxy Landing Page
    hide-navbar: true
    landing-page: /
    port: 8080
    docker:
      internal-networking: true
    specs:
    - id: id1
      display-name: xxx
      description: yyy
      container-cmd: ["/usr/bin/shiny-server.sh"]
      container-image: telethonkids/zzz
      container-env:
        user: 'shiny'
        environment:
          - APPLICATION_LOGS_TO_STDOUT=false
  </code></pre>
  
  <p>Shinyproxy Dockerfile:</p>
  
  <pre><code>FROM openjdk:8-jre
  
  RUN mkdir -p /opt/shinyproxy/
  RUN wget https://www.shinyproxy.io/downloads/shinyproxy-2.1.0.jar -O /opt/shinyproxy/shinyproxy.jar
  COPY application.yml /opt/shinyproxy/application.yml
  
  WORKDIR /opt/shinyproxy/
  CMD ["java", "-jar", "/opt/shinyproxy/shinyproxy.jar"]
  </code></pre>