title: Can't access internet from docker container
body: <p>I'm running to this error while trying to run zotonic from a docker container (using zotonic/zotonic-dev), It seems that I can't connect to the the internet from the container. I've tried using solutions in <a href="https://stackoverflow.com/questions/20430371/my-docker-container-has-no-internet">My docker container has no internet</a> but none seems to work, or maybe I'm skipping something?</p>
  
  <p>I started it using <code>docker-compose run --service-ports zotonic sh</code></p>
  
  <pre><code>Building Zotonic for the first time.
  EXOMETER_PACKAGES="-afunix -netlink -exo +setup" &amp;&amp; ./rebar -C rebar.config.lock get-deps
  WARN:  Missing plugins: [rebar_lock_deps_plugin]
  ==&gt; zotonic (get-deps)
  Pulling goldrush from {git,"git://github.com/DeadZen/goldrush.git",
                             "71e63212f12c25827e0c1b4198d37d5d018a7fec"}
  Cloning into 'goldrush'...
  fatal: Unable to look up github.com (port 9418) (Try again)
  ERROR: sh(git clone -n git://github.com/DeadZen/goldrush.git goldrush)
  failed with return code 128 and the following output:
  Cloning into 'goldrush'...
  fatal: Unable to look up github.com (port 9418) (Try again)
  
  ERROR: 'get-deps' failed while processing /opt/zotonic: rebar_abort
  make: *** [GNUmakefile:40: get-deps] Error 1
  Erlang/OTP 20 [erts-9.0] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:10] [kernel-poll:true]
  </code></pre>