title: Circleci: How to deploy depending on git tag
body: <p>Is there a way to restrict circleci deployment on checkings that have a specific git tag?</p>
  
  <p>Currently I am using this </p>
  
  <pre><code>...
  deployment:
    dockerhub:
      branch: master
      commands:
        - docker login -e $DOCKER_EMAIL -u $DOCKER_USER -p $DOCKER_PASS
        - docker push abcdef
  </code></pre>
  
  <p>Instead of <code>branch: master</code> I would like to write something like <code>tag: /release_.*/</code></p>
  
  <p>Background: I would like to set docker tags depending on git tags. So for example, whenever something is committed to master, a new docker images with <code>latest</code> tag will be created and pushed. Whenever a special git tag is set (e.g. <code>release_1.0_2015-06-13</code>) a new docker image with a tag <code>1.0</code> will be created and pushed.</p>
  
  <p>Alternative is to only use different branches according to the different tags. But I would like to use tags to mark a specific release.</p>