Bringing in some sanity checks from the old database system.

1.  `make check` now runs some SQL queries against the database to check things that aren't easily captured in SQL constraints.
2.  `make reports` produces some CSV-formatted statistical reports.
3.  `db.sql` updated to contain latest faked database.

These reports should all be moved into the application, and rewritten to use Django's ORM. Their output should be formatted for easy copy/pasted, and the statistical reports (e.g., workshops and enrolment over time) should be accompanied by graphs - we need these frequently.