How to set up email verification using PHP CodeIgniter

Database Structure: 

	CREATE TABLE `users` (
	`userid` int(11) NOT NULL AUTO_INCREMENT,
	`first_name` varchar(20) NOT NULL,
	`last_name` varchar(20) NOT NULL,
	`password` varchar(20) NOT NULL,
	`email` varchar(50) NOT NULL,
	`is_verified` int(1) NOT NULL DEFAULT '0',
	`hash` varchar(32) NOT NULL,
	PRIMARY KEY (`userid`)
	)

Controller: 

	<?php
	function insert_user() {
	$this->data = array( //$data is a global variable
	'first_name' => $_POST['fname'],
	'last_name' => $_POST['lname'],
	'email' => $_POST['email'],
	'password' => md5($_POST['password']),
	'hash' => md5(rand(0, 1000))
	);
	$this->user_registration_model->insert_record($this->data);
	}
	?>

<?php
	function send_confirmation() {
	$this->load->library('email'); //load email library
	$this->email->from('admin@mysite.com', 'My Site'); //sender's email
	$address = $_POST['email']; //receiver's email
	$subject="Welcome to MySite!"; //subject
	$message= /*-----------email body starts-----------*/
	'Thanks for signing up, '.$_POST['fname'].'!
	Your account has been created.
	Here are your login details.
	-------------------------------------------------
	Email : ' . $_POST['email'] . '
	Password: ' . $_POST['password'] . '
	-------------------------------------------------
	Please click this link to activate your account:
	' . base_url() . 'index.php/user_registration/verify?' .
	'email=' . $_POST['email'] . '&hash=' . $this->data['hash'] ;
	/*-----------email body ends-----------*/
	$this->email->to($address);
	$this->email->subject($subject);
	$this->email->message($message);
	$this->email->send();
	}
	?>

<?php
	function verify() {
	$result = $this->user_registration_model->get_hash_value($_GET['email']);
	if($result){
	if($result['hash']==$_GET['hash']){
	$this->user_registration_model->verify_user($_GET['email']);
	}
	}
	}
	?>

Model: 

	<?php
	function verify_user($email) {
	$data = array('is_verified' => 1);
	$this->db->where('email', $email);
	$this->db->update('users', $data);
	}
	?>