title: how to get specific users from django user in another model
body: <p>I have this model called <strong>UserTypes</strong> in this model i use User as OneToOne field and <strong>UserTypes</strong> model is inline with <strong>User</strong> model. I created this model to give the user a status just like we do is_staff=True.
  now i want to display all the users whose staff_status = "Delivery Boy" in another model called Order which is in another app in the same project </p>
  
  <p>model.py(app1)</p>
  
  <pre><code>class UserTypes(models.Model):
      user = models.OneToOneField(User, on_delete=models.CASCADE)
      staff_choices = (
          ('', ''),
          ('Admin', 'Admin'),
          ('Chef', 'Chef'),
          ('Delivery Boy', 'Delivery Boy'),
      )
      staff_status = models.CharField(max_length=15, choices=staff_choices, default=staff_choices[0][0]) 
  
      def __str__(self):
          return self.staff_status
  </code></pre>
  
  <p>model.py(app2)</p>
  
  <pre><code>class Order(models.Model):
      name = models.CharField(max_length=60)
      email = models.EmailField(max_length=60,default=None, blank=True)
      mobile_no = models.CharField(max_length=13, default=None) 
      address = models.CharField(max_length=150)
      created = models.DateTimeField(auto_now_add=True)
      updated = models.DateTimeField(auto_now=True)
      status_choices = (
          ('In Queue', 'In Queue'),
          ('Processing', 'Processing'),
          ('Ready', 'Ready'),
          ('Delivered', 'Delivered'),
          ('Paid', 'Paid'),
          ('Cancelled', 'Cancelled'),
      ) 
      status = models.CharField(max_length=15, choices=status_choices, 
              default=status_choices[0][0])
      total = models.DecimalField(max_digits=10, decimal_places=2,default=0)
  
  
  class Meta:
      ordering = ('created', )
  
  
  def __str__(self):
      return 'Order {}'.format(self.id)
  
  
  def get_total(self):
      return sum(item.get_cost() for item in self.items.all())
  </code></pre>