enable-rata-rest-api.php

<?php
/**
 * Add REST API support to an already registered post type.
 */
add_action( 'init', 'rata_post_type_rest_support', 25 );
function rata_post_type_rest_support() {
	global $wp_post_types;

	// Be sure to set this to the name of your post type!
	$post_type_name = 'rata';
	if( isset( $wp_post_types[ $post_type_name ] ) ) {
		$wp_post_types[$post_type_name]->show_in_rest = true;
		$wp_post_types[$post_type_name]->rest_base = $post_type_name;
		$wp_post_types[$post_type_name]->rest_controller_class = 'WP_REST_Posts_Controller';
	}
}