REST_Controller.php is not working in codeigniter
<p>I am going to use REST_Controller.php to make rest api's. (using codeigniter v3 on ubnatu 15)</p>

<p>from link  <a href="https://github.com/chriskacerguis/codeigniter-restserver" rel="nofollow noreferrer">https://github.com/chriskacerguis/codeigniter-restserver</a> </p>

<p>on calling
localhost/rest_api_ci/api/example/user/1</p>

<p><strong>Showing me error</strong> </p>

<pre><code>Fatal error: Class 'REST_Controller' not found in /var/www/html/rest_api_ci/application/controllers/api/Example.php on line 21
</code></pre>

<p><strong>A look of Example.php file</strong> </p>

<pre><code>&lt;?php

defined('BASEPATH') OR exit('No direct script access allowed');

// This can be removed if you use __autoload() in config.php OR use Modular Extensions
/** @noinspection PhpIncludeInspection */
require(APPPATH.'libraries/REST_Controller.php');


/**
 * This is an example of a few basic user interaction methods you could use
 * all done with a hardcoded array
 *
 * @package         CodeIgniter
 * @subpackage      Rest Server
 * @category        Controller
 * @author          Phil Sturgeon, Chris Kacerguis
 * @license         MIT
 * @link            https://github.com/chriskacerguis/codeigniter-restserver
 */
class Example extends REST_Controller {

    function __construct()
    {
</code></pre>