title: reconfigure timezone inside docker not working
body: <p>First, I configure timezone in my Dockerfile as below, but it fails(as I go inside docker container and execute 'date', only to get a Etc/UTC time).</p>
  
  <pre><code>   FROM selenium/standalone-firefox:3.0.1-aluminum
     USER root
     RUN echo "Asia/Shanghai" &gt; /etc/timezone
     RUN dpkg-reconfigure -f noninteractive tzdata
  </code></pre>
  
  <p>Then, I try again as below, it seems 'dpkg-reconfigure' reset the /etc/timezone. So what's wrong on earth?</p>
  
  <p><a href="https://i.stack.imgur.com/H01PZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/H01PZ.png" alt="enter image description here"></a></p>
  
  <p><strong>Supplement</strong>:
  After I follow the method as BMitch suggested, it does make a step forward, but another confusing problem occurs: date command inside docker container prints a wrong time.
  <a href="https://i.stack.imgur.com/6ZGg8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6ZGg8.png" alt="enter image description here"></a></p>