title: Django_tagging (v0.3/pre): Configuration issue
body: <p>I am trying to use the django-tagging in one of my project and run into some errors.</p>
  
  <p>I can play with tags in the shell but couldn't assign them from admin interface.</p>
  
  <p>What I want to do is add "tag" functionality to a model and add/remove tags from Admin interface.</p>
  
  <p>Why is it the "tags" are seen by shell and not by "admin" interface? What is going on?</p>
  
  <p>Model.py:</p>
  
  <pre><code>import tagging
  
  class Department(models.Model):
      tags = TagField()
  </code></pre>
  
  <p>Admin.py:</p>
  
  <pre><code>class DepartmentAdmin(admin.ModelAdmin):
      list_display = ('name', 'tags') --&gt; works
  ....
      fields = ['name', 'tags'] --&gt; throws error
  </code></pre>
  
  <p>Error</p>
  
  <pre><code>    OperationalError at /admin/department/1/
      (1054, "Unknown column 'schools_department.tags' in 'field list'")
  </code></pre>
  
  <p>I looked at the docs and couldn't find further information
  <a href="http://code.google.com/p/django-tagging/wiki/UsefulTips" rel="nofollow noreferrer">Useful Tips</a>
  <a href="http://code.google.com/p/django-tagging/source/browse/trunk/docs/overview.txt" rel="nofollow noreferrer">Overview Txt</a></p>