title: IntegrityError at /admin/course/course/add/ in django
body: <p>I got this error when I tried to add content or course. It was working fine and now I get this error. I have uploaded it on heroku and it works fine, just in the local dev it won't add anything. Can someone explain whats going wrong. Pls also specify what additional info should I add ?</p>
  
  <pre><code>IntegrityError at /admin/course/course/add/
  
  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".
  
  Request Method:     POST
  Request URL:    http://127.0.0.1:8888/admin/course/course/add/
  Django Version:     1.5.1
  Exception Type:     IntegrityError
  Exception Value:    
  
  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".
  
  Exception Location:     /home/vagrant/sai/local/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py in _commit, line 240
  Python Executable:  /home/vagrant/sai/bin/python
  Python Version:     2.7.3
  </code></pre>