title: How to add multiple models from a Django app to adminpanel?
body: <p>To add a single model from an app in to the <code>/admin</code> area I have done like so:</p>
  
  <pre><code>from django.contrib import admin
  from wiki.models import Page, Category, CategoryItem
  
  # register Pages for use in Django admin
  class PageAdmin(admin.ModelAdmin):
      pass
  admin.site.register(Page, PageAdmin)
  </code></pre>
  
  <p>which works fine for a single model, but when I try to register the other two (Category and CategoryItem), it breaks down. What is the correct way of adding multiple models for a single Django app in the admin interface?</p>