title: What is docker.io in relation to docker-ce and docker-ee (now called "Mirantis Kubernetes Engine")?
body: <p>Previously, to install docker I would use</p>
  
  <pre><code>apt-get install docker.io
  </code></pre>
  
  <p>However, I have recently noticed the documentation for installing docker, and it uses docker-ce. I have tried to find the difference between the two, but have come up empty. What is docker.io in relation to docker-ce?</p>