title: Docker image with python & alpine failure due missing compiler error
body: <p>I'm looking for a docker image with both python3 and a crontab.
  When I use <code>python:latest</code> as a base, I have no cron, but all required python packages install without problem.</p>
  
  <p>When I use alpine as a base I have the (busybox) cron working, but are unable to install specific python package due to compiler error.</p>
  
  <p>The same applies when I use <code>python:alpine</code>.</p>
  
  <pre><code>Collecting pynacl&gt;=1.0.1 (from paramiko-&gt;-r required_python_packages.txt (line 6))
    Downloading PyNaCl-1.1.2.tar.gz (3.1MB)
      Complete output from command python setup.py egg_info:
  
          No working compiler found, or bogus compiler options
          passed to the compiler from Python's distutils module.
          See the error messages above.
  </code></pre>
  
  <p>Any advise?</p>