categories.xml

<data type="array">
  <datum>
    <TCCategory>
      <id type="integer">1</id>
      <name>Dining</name>
      <category-id type="integer">2</category-id>
      <active type="boolean">true</active>
      <position type="integer">1</position>
      <created-at type="datetime">2010-03-26T16:06:12-05:00</created-at>
      <updated-at type="datetime">2010-07-20T14:51:37-05:00</updated-at>
    </TCCategory>
  </datum>
</data>

index.rabl

collection @categories, root: "data", object_root: "TCCategory"

extends "api/legacy/categories/show"

show.rabl

object @category
attributes :id, :name, :category_id, :active, :position, :created_at,
  :updated_at