title: uninitialized constant ModelObserver - Rake task on Heroku
body: <p>Rake task performs ActiveRecord model operations. I added <code>ActiveRecord::Base</code> in the rake task and that works locally, but not on Heroku resulting in this error:</p>
  
  <blockquote>
    <p>uninitialized constant BookingObserver</p>
  </blockquote>
  
  <p>on the line with <code>ActiveRecord::Base</code>. If I do not include that line then I cannot use the model at all <em>(resulting in similar error just for the model not the observer)</em>.</p>