MongoEngine/mongoengine — pull request #586 by wpjunior (2014-02-25 18:46:46+00:00)
Title: db_alias support and fixes for custom map/reduce output

To work:
```python
Person.objects.map_reduce(
map_f=map_person,
reduce_f=reduce_f,
output={'reduce': 'family_map', 'db_alias': 'test2'})