Install django-mptt.
Add apps back to settings to fix migrations.
Fix bug 964783: Create initial revision of new data models.
Migrate data from old models to new models.

In order for the migration to work successfully, the site will have to
run the migrations on this exact commit. Otherwise, the migrations that
these depend will be gone, as the badges app is going to be deleted.
Remove old models.
Document migration process.
Remove badges and news apps, and reset migrations for banners and links.

Once on this commit, you will have to migrate both the links and banners
apps back down to 0001, using the --fake flag to avoid making actual 
database changes, and the --delete-ghost-migrations flag to delete the
leftover migrations that get deleted.
Update migration docs.