Assume you have a model
Disc and a disc has many songs, on the
Song migration you would declare the disc_id as a foreign_key, and then on
class DiscRepository < Hanami::Repository
This way you will be able to call
disc.songs although you won't have all the Rails methods like
disc.songs.where(title: 'My song) and that's because the
songs method will return a simple array.
As you can se, we need to explicitly create methods that use the association in order to not bloat your repository with association methods when it's not needed.
Sorry for taking so long to reply, I was very busy lately.