1.php

$this->load->library('tank_auth');
		

1.sql

ALTER TABLE users ADD group_id INT NOT NULL DEFAULT '300'

2.php

$this->load->library('tank_auth_groups','','tank_auth');

admin.php

<?php

// application/controllers/admin.php

require 'admin_base.php';

class Admin extends Admin_Base {
    
    function index()
    {
        redirect('admin/dashboard');
    }

    function dashboard()
    {
        // display admin dashboard
    }
}

?>

admin_base.php

<?php

// application/controllers/admin_base.php

class Admin_Base extends CI_Controller {
    
   function __construct()
   {
      parent::__construct();
                
      $this->load->library(
         'tank_auth_groups', '', 'tank_auth'
      );
                
      if(!$this->tank_auth->is_admin())
      {
         redirect('auth/login');
      }
   }
} 

?>