anchor.diff:  
   ==== Links
   
  +In general, links for relationships will be provided when the relationship has a value.
  +
  +Example output for a has one relationship where the value is null:
  +
  +[source,json]
  +"captain": {
  +  "data": null
  +}
  +
  +And when the value is not null:
  +
  +[source,json]
  +"author": {
  +  "links": {
  +    "self": "/author/9"
  +  },
  +  "data": {
  +    "type": "author",
  +    "id": "9"
  +  }
  +}
  +
  +In the case of to many relationships, the JSON API specification only allows a single links object for the collection. Due to no enforced standard for how to link to those nested resources, a link will not be included in the response.
  +
   ==== Pagination
  +
  +The JSON API specification has a section which explains http://jsonapi.org/format/#fetching-pagination[pagination]. The Grails implementation follows that specification as it is written.
  +
  +To enable pagination links in your output you must be rendering a collection and also include some arguments in addition to the collection being rendered. There are two required arguments: total and resource. The default offset is 0 and max is 10.
  +
  +[source,groovy]
  +model {
  +    List<Book> books
  +    Integer bookTotal
  +}
  +json jsonapi.render(books, [pagination: [total: bookTotal, resource: Book]])
  +
  +Example links output if `bookTotal == 20`:
  +
  +[source,json]
  +links": {
  +  "self": "/books",
  +  "first": "http://localhost:8080/books?offset=0&max=10",
  +  "next": "http://localhost:8080/player?offset=10&max=10",
  +  "last": "http://localhost:8080/player?offset=10&max=10"
  +}
  +
  +By default the values for `offset`, `sort`, `max`, and `order` will come from the parameters with the same names. You can override their values by passing the corresponding argument in the pagination Map.
  +
  +[source,groovy]
  +model {
  +    List<Book> books
  +    Integer bookTotal
  +}
  +json jsonapi.render(books, [pagination: [total: bookTotal, resource: Book, max: 20, sort: params.myCustomSortArgument]])
   
   ==== Associations
   
  
positive.code:     }
    },
    "links": {
      "self": "http://localhost:8080/book/3",
      "related": {
        "href": "http://localhost:8080/author/9"
      }
    }
  }
  
  
negative.code:     },
      "relationships": {
        "author": {
          "links": {
            "self": "/author/9"
          },
          "data": {
            "type": "author",
            "id": "9"
  