Add test for creating sticky post.
Add tests to confirm posts response includes pagination headers.
Add tests for pagination parameters to get_items type parameter tests.
Add tests for invalid get_items and get_item responses.
Correct pagination parameters.
Set author_id property when setting up class to avoid creating a bunch of users.
Use approach from old style Posts tests to set default post data to use when creating a new post.
Allow posts to be created with JSON data.
Add delete post route, controller logic and unit tests.
Rename author_id property to editor_id in posts unit tests.
Add _links array to post response.