okfn/foundation — pull request #152 by tryggvib (2014-04-14 00:01:08+00:00)
Title: organisation: allow many themes for each working group

Move the current single foreign key theme to a manytomanyfield
themes and migrate the data as well.

Since it is bad practice to mix schema and data migrations this
calls for three separate migrations:

1. Add the many to many field (themes)
2. Migrate the data (add value of theme to themes)
3. Remove the foreign key (theme)

Fixes #128