title: Linking django and mysql containers using docker-compose
body: <p>I've been following with the docker-compose tutorial <a href="https://docs.docker.com/compose/django/" rel="noreferrer">here</a> (linking django and postgres container). Although I was able to go through with the tutorial I'm however not able to proceed with repeating the same
  using a mysql container.
  The following are my dockerfile and docker-compose.yml
  `</p>
  
  <pre><code>db:
    image: mysql
  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000"
    links:
      - db:db
  </code></pre>
  
  <p>`
  dockerfile</p>
  
  <pre><code>FROM python:2.7
  RUN mkdir /code
  WORKDIR /code
  RUN pip install mysql-python
  RUN pip install django
  </code></pre>
  
  <p>They both build fine when I do <code>docker-compose up</code> but it seems the db environment variables are not passed to the django container since when I run <code>os.environ.keys()</code> in one of my django views I can't see any of the expected DB_* environment variables.
  So does mysql require a different setup or am I missing something.
  Thank you.</p>
  
  <p>[EDIT]
  Docker compose version</p>
  
  <pre><code>docker-compose version: 1.3.0
  CPython version: 2.7.9
  OpenSSL version: OpenSSL 1.0.1e 11 Feb 2013
  </code></pre>
  
  <p>Docker version</p>
  
  <pre><code>Docker version 1.6.2, build 7c8fca2
  </code></pre>