Rails + Ember: Nested models incorrect format

I have a Rails API and I am trying to pull in records in Ember and while its working, my nested model is not. I have an Employee that belongs_to a Location and have created a serializer like so:

class API::EmployeeSerializer < ActiveModel::Serializer
  attributes :id, :name, :phone, :email, :manager, :terminated, :location
  belongs_to :location
end

which outputs:

{"employee":
    {"id":19,"name":"John Abreu","phone":"","email":"","manager":false,"terminated":false,"location":
        {"name":"Peabody","id":2}
    }
}

and my ember app pulls this in through:

import Ember from 'ember';

export default Ember.Route.extend({
    model() {
        return this.store.findAll('employee')
    }
});

but I hit my error when I encounter the location portion of the hash. I get the following:

> Assertion Failed: Ember Data expected the data for the location
> relationship on a <employee:19> to be in a JSON API format and include
> an `id` and `type` property but it found {name: Peabody, id: 2}.
> Please check your serializer and make sure it is serializing the
> relationship payload into a JSON API format.

How can I correct this? I already have a LocationSerializer that has:

class LocationSerializer < ActiveModel::Serializer
  attributes :id, :phone, :address, :name
end