title: Docker compose volumes
body: <p>While searching for a docker-compose file I came across this. I saw that the volumes having 2 instructions I'm pretty sure that 2nd one is mapping but I don't know what's the 1st one.</p>
  <pre><code> volumes:
    - /app/node_modules
    - ./server:/app
  </code></pre>
  <p>I</p>