title: django change list display column name with foreign field value
body: <p>I am using <code>django 1.9</code> , i have following model which have two foreing fields,</p>
  
  <p><strong>models.py</strong></p>
  
  <pre><code>class Mobile(models.Model):
      name = models.CharField(max_length=100)
      product = models.ForeignKey(Product)
      owner = model.ForeignKey(Customer)
  </code></pre>
  
  <p>now i want to build a admin interface for <code>Mobile</code> model where i want to provide list display for both <code>product</code> and <code>owner</code> foreign  fields,that is, the list display will show one of the field of that foreign fields and also want to change the column name,i have tried so but its not working at all</p>
  
  <p><strong>admin.py</strong></p>
  
  <pre><code>class MobileModelAdmin(admin.ModelAdmin):
     list_display = ('name','product', 'owner')
  
      def related_product(self, obj):
          return obj.product.name
      related_product.short_description = 'product name'
  
      def related_owner(self, obj):
          return obj.owner.name
      related_owner.short_description = 'owner name'
  
  admin.site.register(Mobile, MobileModelAdmin)
  </code></pre>
  
  <p>but neither its changing the column name nor showing the related value.</p>