I would like to make a relation using a different way then the classic
belongs_to/has_many association. Instead of this, I would like to save
the foreign key in the parent class as a list of ids.
For instance, we can consider 2 models: File and Folder.
Basically, we could add in File model this method: folder_id.
But can we do the same with a list of file’s ids stored in this folder’s