Generally, it is useful to have the primary key get returned from an insert call in an ORM, so that you can insert rows into other tables and reference that newly created row in the primary table, do HTTP redirects using that primary key, etc etc etc.
Currently repo.insert return is void which is not very helpful.
Looking briefly at the PostgreSQL docs, it appears that the INSERT INTO <> VALUES <> RETURNING id seems to be the general practice for PostgreSQL