title: extend jenkins image to install maven
body: <p>I'm using the <code>jenkins/jenkins:lts</code> image at the moment. It runs fine and does everything I want to expect one thing. I want it to run Maven goals in the build steps. The problem is that there is not maven installed in the jenkins container environment.</p>
  
  <p>So I want to extend the mentioned image to run an <code>apt-get install maven</code>.</p>
  
  <p>My solution:</p>
  
  <pre><code>FROM "jenkins/jenkins:lts
  USER root
  RUN /bin/bash -c "apt-get install maven"
  </code></pre>
  
  <p>Will this be enough? I assume that all RUN and ENTRYPOINT steps of the jenkins image will run by itself and I do not need to re-execute them in my Dockerfile right?</p>