Implementing datatables in codeigniter

Hello everyone! I have a working datatables in plain php a few months ago. Now that I'm studying CodeIgniter, I want to implement datatables server side. The problem is how do I do it? I have this following code.

views:

<script type="text/javascript">
	$(document).ready(function() {
		$('#users_table').dataTable({
			"sScrollX": "100%",
			"sScrollXInner": "100%",
			"sPaginationType": "full_numbers",
			"bProcessing": true,
			"bServerSide": true,
			"bJQueryUI": true,
			"bDeferRender": true,
			"sAjaxSource": '<?php echo base_url(); ?>/users/get_active_users'
		});
	});
</script>
<table id="users_table">
					<thead>
						<tr>
							<th>Username</th>
							<th>Full Name</th>
							<th>Office</th>
							<th>Position</th>
							<th>Email</th>
							<th>Privilege</th>
							<th>Date Registered</th>
						</tr>
					</thead>
					<tbody></tbody>
</table>

model:

public function active() {
		$query = $this
					->db
					->select('username, last_name, office, email, privilege, datetime_registered')
					->where('status', 'Active')
					->where('username !=', $this->session->userdata('username'))
					->get('users');
		return $query->result(); //return result to array
	}

controller:

public function get_active_users() {
		$results = $this->user_management->active(NULL, TRUE);
		echo json_encode($results);
	}

Screenshot: http://imageshack.us/a/img163/6937/93541166.png