celery/celery — pull request #1990 by ocean1 (2014-04-17 18:49:22+00:00)
Title: mongodb native serialization and group results meta collection

a little more flexible approach on storing data effectively on mongodb allowing to map-reduce/aggregate eventually:
- added a groupmeta_collection option to save group results in a different collection than results
- added a 'bson' fake kombu encoder to allow pymongo to serialize natively data in mongodb