title: Integrity error on django_admin_log after updating existing site to new Django 1.5 user model
body: <p>Apparently after adding my new user table to the site, django_admin_log still has a FK to auth_user table.  Any way to address this? I didn't see this problem in staging or locally so something odd must have taken place. </p>
  
  <p><strong>Traceback</strong> (most recent call last) <strong>:</strong></p>
  
  <blockquote>
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/core/handlers/base.py", line 115, in get_response
        response = callback(request, *callback_args, **callback_kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/newrelic-1.10.0.28/newrelic/api/object_wrapper.py", line 220, in <strong>call</strong>
        self._nr_instance, args, kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/newrelic-1.10.0.28/newrelic/hooks/framework_django.py", line 475, in wrapper
        return wrapped(*args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/admin/options.py", line 372, in wrapper
        return self.admin_site.admin_view(view)(*args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/decorators.py", line 91, in _wrapped_view
        response = view_func(request, *args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/views/decorators/cache.py", line 89, in _wrapped_view_func
        response = view_func(request, *args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/admin/sites.py", line 202, in inner
        return view(request, *args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/decorators.py", line 25, in _wrapper
        return bound_func(*args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/decorators.py", line 91, in _wrapped_view
        response = view_func(request, *args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/decorators.py", line 21, in bound_func
        return func(self, *args2, **kwargs2)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/transaction.py", line 223, in inner
        return func(*args, **kwargs)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/transaction.py", line 217, in <strong>exit</strong>
        self.exiting(exc_value, self.using)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/transaction.py", line 281, in exiting
        commit(using=using)</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/transaction.py", line 152, in commit
        connection.commit()</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/<strong>init</strong>.py", line 241, in commit
        self._commit()</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 242, in _commit
        six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 240, in _commit
        return self.connection.commit()</p>
    
    <p>File "/app/.heroku/python/lib/python2.7/site-packages/newrelic-1.10.0.28/newrelic/hooks/database_dbapi2.py", line 68, in commit
        return self._nr_connection.commit()</p>
    
    <p>IntegrityError: insert or update on table "django_admin_log" violates foreign key constraint "django_admin_log_user_id_fkey"
    DETAIL:  Key (user_id)=(2) is not present in table "auth_user".</p>
  </blockquote>