title: Django admin list filter on reverse relationship
body: <p>I have two django models:</p>
  
  <pre><code>class Order(models.Model):
      date = models.DateTimeField()
      customer = models.ForeignKey(Customer, on_delete=models.CASCADE, related_name='orders')
      shipping_address = models.CharField(max_length=200)
      phone_number = models.CharField(max_length=9)
      comment = models.CharField(max_length=100, blank=True, null=True)
  
  class OrderStatus(models.Model):
      STATUS_ACCEPTED = 1
      STATUS_PROCESSING = 2
      STATUS_DELIVERING = 3
      STATUS_COMPLETED = 4
      CODE_CHOICES = (
          (STATUS_ACCEPTED, 'accepted'),
          (STATUS_PROCESSING, 'processing'),
          (STATUS_DELIVERING, 'delivering'),
          (STATUS_COMPLETED, 'completed'),
      )
      date_created = models.DateTimeField(auto_now_add=True)
      code = models.PositiveSmallIntegerField(choices=CODE_CHOICES)
      order = models.ForeignKey(Order, on_delete=models.CASCADE, related_name='status_list')
  </code></pre>
  
  <p>Normally if I wanted to get all the orders with 'accepted' status I could write Order.objects.filter(orderstatus__code=1). </p>
  
  <p>But how can I make django admin to create OrderStatus list filter? </p>
  
  <p>I have googled a lot and found only one answer here on stackoverflow, which claims simply adding reverse model ('orderstatus' in my case) to list_filter tuple should work, but I get an error message: <code>The value of 'list_filter[1]' refers to 'orderstatus', which does not refer to a Field.</code></p>
  
  <p>What am I doing wrong?</p>