title: Django- filtering results where one or more reverse foreign keys meet criteria
body: <p>Lets say I have the following (simplified) models:</p>
  
  <pre><code>class Job(models.Model):
      name = models.CharField(max_length=255)
  ​    
  class JobDateStatus(models.Model)
      job = models.ForeignKey(Model, on_delete=models.CASCADE)
      date = models.DateField()
      status = models.CharField(max_length=6)
  </code></pre>
  
  <p>Is there a way to select all <code>Job</code> objects where any (one or more) of its <code>JobDateStatus</code> children have a particular status?  e.g.:</p>
  
  <pre><code>active_jobs = Job.objects.filter(&lt;ONE OR MORE OF jobdatestatus_set HAS status='active'&gt;)
  </code></pre>