title: Pull Docker from my private docker-registry without specifying the host
body: <p>I am using docker-registry to pull my own docker images, but I want to do so without the need to specify the host. meanning:
  instead of writing:</p>
  
  <pre><code>docker pull &lt;host&gt;:&lt;port&gt;/&lt;dockerImage&gt;
  </code></pre>
  
  <p>I want to write:</p>
  
  <pre><code>docker pull &lt;dockerImage&gt;
  </code></pre>
  
  <p>and first it will try to pull the docker from my private registry, before trying to pull it from the public docker registry.</p>
  
  <p>Is it possible?</p>
  
  <p>I tried to change the <code>DOCKER_INDEX_URL</code> to <code>[my_docker_registry_host]:[port]</code>, but it doesn't work.</p>