title: django keyword can't be an expression
body: <p>I am trying to create a query where I get a filtered list.</p>
  
  <p>The model that I am calling the query on is:</p>
  
  <pre><code>class WorkoutRecord(models.Model):
  
      challenge = models.ForeignKey(Challenge)
  
      workout_email_sent = models.DateTimeField(default=datetime.now)
  
      status = models.IntegerField(default=1) 
  </code></pre>
  
  <p>My query is:</p>
  
  <pre><code>L = WorkoutRecord.objects.filter(status = 1, challenge.user = request.user, workout_email_sent__lt = today)
  </code></pre>
  
  <p>The error message I am getting is:</p>
  
  <blockquote>
    <p>keyword can't be an expression</p>
  </blockquote>
  
  <p>I know the issue is on the <code>challenge.user = request.user</code> part of the query but I'm not sure how to write the query so it filters on this <code>ForeignKey</code> properly.</p>