posts.json

{
  "data": [
    {
      "id": "1",
      "type": "posts",
      "attributes": {
        "title": "First post"
      },
      "relationships": {
        "comments": {
          "data": [
            {
              "id": "5",
              "type": "comments"
            }
          ]
        }
      }
    },
    {
      "id": "2",
      "type": "posts",
      "attributes": {
        "title": "Second post"
      },
      "relationships": {
        "comments": {
          "data": [
            {
              "id": "3",
              "type": "comments"
            }
          ]
        }
      }
    }
  ],
  "included": [
    {
      "id": "3",
      "type": "comments",
      "attributes": {
        "body": "first!"
      }
    },
    {
      "id": "5",
      "type": "comments",
      "attributes": {
        "body": "inane drivel"
      }
    }
  ]
}