Ran Migrations.

Not really sure what changed here.
Added Tests for get_opinion_counts

Added tests for aggregation and return of get_opinion_counts, adding it
to admin listing as well.
Added category to admin.

Added more view tests for Questions listing.
404 if Questions request from Nonexistent Category

Returning 404 if a questions listing is for a category which doesn't
exist. Only if the list is empty to do we perform this check since
that's the only time we really need to check it anyway.