I updated mongoid from version 2 to version 3, and my script is broken now.

h =

{key: group_field, cond: cond, initial: initial_params, reduce: func}

User.collection.group(h)

(User - my model, h - hash with options)

I can't find anything about this problem in google or at this page: http://mongoid.org/en/mongoid/docs/upgrading.html

I want to use Group ( http://www.mongodb.org/display/DOCS/Aggregation#Aggregation-Group ). How I can do it with mongoid3?