dimagi/fluff — pull request #43 by snopoke (2013-08-20 15:21:48+00:00)
Title: allow specifying of expected group_by types

Useful if you're linking with ctable.

e.g.
The following will result in an `age` column in SQL that is of *integer* type.
```
group_by = ('age',)
group_by_type_map = {'age': TYPE_INTEGER}
```