title: How to allow multiple '--insecure-registry' for docker registry
body: <p>As we all known, we can add one <code>--insecure-registry</code> to the <code>/etc/default/docker</code> config file to allow insecure registry, like this:</p>
  
  <pre><code>DOCKER_OPTS="$DOCKER_OPTS --insecure-registry myregistry:5000"
  </code></pre>
  
  <p>My question is: Does it support adding more than one <code>--insecure-registry</code> since we need to communicate with more than one registries ?</p>