title: How to pass arguments within docker-compose?
body: <p>Docker 1.9 allows to pass arguments to a dockerfile. 
  See link: <a href="https://docs.docker.com/engine/reference/builder/#arg" rel="noreferrer">https://docs.docker.com/engine/reference/builder/#arg</a>  </p>
  
  <p>How can I pass the same arguments within docker-compose.yml?<br>
  Please provide an example too, if possible.  </p>