Create/update with FK relationships

[threewordphrase]

If looks like if I am trying to create or update an object with a relationship to foo, I need to send a payload like "foo": 1 instead of "foo_id": 1?

How can I fix this? I am returning embedded relationships in my API endpoints, so my foo attribute when read out is actually the Foo object. It is going to significantly increase complexity on my frontend if foo is sometimes the embedded object and sometimes the foreign key.

The column on the model is called foo_id, I should be able to create and update using foo_id.