Add database migration code.

All of the files under <app name>\migrations\ are auto generated by
south. These get generated by running the command:
manage.py schemamigration <app_name>--auto
This command should get run whenever an app's models change. Once this
command is run, also run:
manage.py migrate <app_name>

I verified the change works by making minor changes to the Jobs model
and the InternNestUser model.

Fixes #10
Merge branch 'master' of https://github.com/Sliverb/PandaFactor