title: How can I fix this error with Wagtail CMS?
body: <p>I just setup Wagtail CMS in Django and when I run <code>django-admin runserver</code> I get the following errors:</p>
  
  <pre><code>ERRORS:
  wagtaildocs.Document.tags: (fields.E300) Field defines a relation with model 'Tag', which is either not installed, or is abstract.
  wagtailimages.Image.tags: (fields.E300) Field defines a relation with model 'Tag', which is either not installed, or is abstract.
  
  System check identified 2 issues (0 silenced).
  </code></pre>