title: Django periodic tasks in Celery
body: <p>i"m having this issue with periodic tasks not running. I"m using redis as a backend and can run the tasks manually, this is the celery debug log </p>
  
  <pre>
  
      [ModelEntry: myproject.myapp.tasks.MyPeriodicTask myproject.myapp.tasks.MyPeriodicTask(*[], **{}) { freq: 10.00 seconds }]
      [2012-08-01 13:45:53,764: DEBUG/MainProcess] Consumer: Ready to accept tasks!
      [2012-08-01 13:45:53,801: DEBUG/Beat] Celerybeat: Ticking with max interval->5.00 seconds
      [2012-08-01 13:45:53,808: DEBUG/Beat] Celerybeat: Waking up in 5.00 seconds.
      [2012-08-01 13:45:58,814: DEBUG/Beat] Celerybeat: Waking up in 5.00 seconds.
      [2012-08-01 13:46:03,828: DEBUG/Beat] Celerybeat: Waking up in 5.00 seconds.
  
  </pre>
  
  <p>When i run the task manually, everything works.
  Timezone is the same in django and celery</p>