response.json

{
  "data": [
    {
      id: 1,
      type: "foo",
      relationships: {
        "bars": {
          data: [
            { id: 2, type: "bar" }
          ]
        }
      }
  ],
  "included": [
    {
      id: 2,
      type: "bar",
      attributes: {
        baz: "zed"
      }
    }
  ]
}