title: Docker-compose copy config
body: <p>I am trying to create a docker-compose for a project that requires a service to be running in the background. The image for service exists and this contains a config file, as well as an entrypoint ["/usr/bin/java", ...]</p>
  
  <p>I would like to change the content of configuration file but I am not sure what would be the best way to do it without creating an extra dockerfile to just recreate image with appropriate files?</p>
  
  <p>Since the entrypoint is /usr/bin/java , I am not sure how I would be able to use docker-compose's command to modify file content. </p>
  
  <pre><code>version: 2
  services:
    myService:
      image: serviceA from registry
       # Would like to modify a config file's content...
  
    mainAPI:
       ...
  </code></pre>
  
  <p>Thank you</p>