re #1: Fixed failing test in data loader

This causes the test to exception because the record was being
accessed before it was in the database.
re #1: Added a `store` method to `FestivalData`

This persists the drink data in the database.

Also update the loader test for `WBF` to add a simple check for the
`store` method and subsequent `DrinkRecord` access
re #1: Updated core to use database access via `FestivalData`

Tests are also updated, but now require that the database is
initialised and the `FestivalData` loaded for each test.