title: Sharing /tmp between two containers
body: <p>I'm using <code>docker-compose</code> to spawn two containers. I would like to share the <code>/tmp</code> directory between these two containers (but not with the host <code>/tmp</code> if possible). This is because I'm uploading some files through <code>flask</code> to <code>/tmp</code> and want to process these files from <code>celery</code>.</p>
  
  <pre><code>flask:
      build: .
      command: "gulp"
      ports:
          - '3000:3000'
          - '5000:5000'
      links:
          - celery    
          - redis
      volumes:
          - .:/usr/src/app:rw
  
  celery:
      build: .
      command: "celery -A web.tasks worker --autoreload --loglevel=info"
      environment:
          - C_FORCE_ROOT="true"
      links:
          - redis
          - neo4j
      volumes:
          - .:/usr/src/app:ro
  </code></pre>