title: Django 1.4 - extend user model and admin interface
body: <p>Let's have 2 models that extends the user model called <code>Ext1</code> and <code>Ext2</code> declared as follow:</p>
  
  <pre><code>class ExtN(models.Model):
      user = models.OneToOneField(User)
      extra_param = models.xxxField()
  </code></pre>
  
  <p>then I declare in application specific <code>admin.py</code> file something like:</p>
  
  <pre><code>class ExtNInline(admin.StackedInline):
      model = ExtN
      can_delete = False
  </code></pre>
  
  <p>in which file do I need to put the following code, in order to see the form to edit both models related to the user?</p>
  
  <pre><code>class UserAdmin(UserAdmin):
      inlines = (Ext1Inline, Ext2Inline, )
  
  admin.site.unregister(User)
  admin.site.register(User, UserAdmin)
  </code></pre>
  
  <p>Thanks in advance.</p>