title: Rails migrations task already started error
body: <p>I have a Rails that is currently deployed on Kubernetes. The entrypoint of the app's image is this script: </p>
  
  <pre><code>#!/bin/sh
  set -e
  
  cd /usr/src/app
  
  foreman run bundle exec rake db:migrate
  
  exec "$@"
  </code></pre>
  
  <p>We have around 10 pods and all of them run the same startup command.<br>
  Now, everytime I redeploy, apply something, every time the pod is restarted, I see this on console:</p>
  
  <pre><code>E, [2018-03-06T11:10:26.212305 #9] ERROR -- : RAKE_TASK_INFO: task db:migrate started at 06-03-18 11:10:26 UTC
  </code></pre>
  
  <p>I think that I had a concurrency issue before when I fired up 10 pods and they all tried to run <code>rails db:migrate</code> and now I have the feeling that something is horribly wrong.  </p>
  
  <p>Is there something I can do? Something on the database to remove the lock? I tried to shutdown all pods and restart but I see the same message on console</p>