title: How to calculate return to depot time and make it hard constraint
body: <p>I am using the TimeWindowed version of the vehicle routing and I added to the vehicle an endOfShift time. I want to calculate the time of return to depot and make it hard constraint. 
  The returnToDepotTime is calculate in the ArrivalTimeUpdatingVariableListener, and I also changed the drl file I added </p>
  
  <pre><code>rule "returnToDepotBeforeEndOfShift"
  when
      Vehicle(endOfShift &lt; returnToDepotTime, $endOfShift : endOfShift, $returnToDepotTime : returnToDepotTime)
  then
      scoreHolder.addHardConstraintMatch(kcontext, $endOfShift - $returnToDepotTime.intValue());  end
  </code></pre>
  
  <p>The problem is that OptaPlanner does not take returnToDepotTime into consideration and it is calculated but not taken by the hard constrains calculation. Any idea what to change?</p>