Fix 1+n requests problem
To retrieve linked entity by foreign key, you have to use a custom field parser that queries the DB for each field: https://github.com/moigagoo/norm-sample-webapp/blob/develop/src/models.nim#L19

This is super unoptimal and causes 1+n requests where one would do.

The right way to do it is to query the DB with ``JOIN`` when retreiving the entity and put the extra fields in a linked entity.