Multiple admin areas & user identification - best approach?

I am completely new to CodeIgniter, so please bear with me. 

To better understand and learn how CodeIgniter works, I am currently building a sample job board application with a login area using Ion Auth. The idea here is to have a super administrator, who has complete access to edit and manage users, posts, settings etc. and a normal user group, that can post and edit only their own jobs and profile details.

With this in mind, I would like to show different admin-areas with different functions to the different user groups; one for the super-admin and one for the normal users.

My question now is, how to organize these two admin-dashboards.

I currently use a single controller "Dashboard.php" to basically load different menu-views depending on the users status (admin vs non-admin):

PHP Code:

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

class Dashboard extends MY_Controller
{
    function __construct()
    {
        parent::__construct();

        // Load authentication library
        $this->load->library('ion_auth');

        // Check user status
        if (!$this->ion_auth->logged_in())
        {
            redirect('auth/login');
        }
    }

    public function index()
    {
        if ($this->ion_auth->is_admin()) {
            $this->load->view('common/header');
            $this->load->view('dashboard/top_nav_admin');
            echo 'This is the administrators page';
            $this->load->view('common/footer');
        } else {
            $this->load->view('common/header');
            $this->load->view('dashboard/top_nav_user');
            $this->load->view('dashboard/index_view');
            $this->load->view('common/footer');
        }

    }
} 


 

I am not sure if this is a good idea or if it is better to have a unique controller for every user group, also in order to define different methods for each group. I don't want to repeat much code regarding the views in the admin-area (i.e. basically same design but different menus).


Also, another question concerns how to identify a specific user once he or she is logged in to the admin-area in order to only show his posts / user details.

Is there a way to get the user ID and for instance save it in a session or what is the best approach here?

Thanks for your feedback.