I've decided to use SQLite for storing data. The database is only going to be a few tables, and I think a full blown database server like PostgreSQL would be overkill for my needs.

Also decided to use Perl Dancer to provide the backend code. Installed from CPAN because the Raspian repositories didn't have Dancer2, while all of the official Dancer documentation has moved on to Dancer2.

Next steps are to come up with the database schema and play with getting data in and out of it.