title: How to fix docker: Got permission denied issue
body: <p>I installed Docker in my machine where I have Ubuntu OS.<br />
  When I run:</p>
  <pre><code>sudo docker run hello-world
  </code></pre>
  <p>All is ok, but I want to hide the <code>sudo</code> command to make the command shorter.<br />
  If I write the command without <code>sudo</code></p>
  <pre><code>docker run hello-world
  </code></pre>
  <p>That displays the following:</p>
  <pre><code>docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.35/containers/create: dial unix /var/run/docker.sock: connect: permission denied. See 'docker run --help'.
  </code></pre>
  <p>The same happens when I try to run:</p>
  <pre><code>docker-compose up
  </code></pre>
  <p>How can I resolve this?</p>