title: Django and absolute url with slug
body: <p>my model is like:</p>
  
  <pre><code>class Modeloxy(models.Model):
        ...
        ...
        slug = models.slug()
  
  
  class mymodel(models.Model):
        marca = ...
        ...
        modelo = models.ForeignKey(Modeloxy)
  
  
        def get_absolute_url(self):
            return '/%s/%s/%s' % (self.marca,self.modelo__slug,self.pk)
  </code></pre>
  
  <p>So, i can't get the absolute url usin self.modelo__slug.... how i will do that?</p>
  
  <p>thanks guys</p>