How can I send a welcome email with the registration system?
function register()
    {
        if(isset($_POST['register'])){
            $this->form_validation->set_rules('username','Username','required|is_unique[accounts.Username]');
            $this->form_validation->set_rules('email','Email','required|is_unique[accounts.Email]');
            $this->form_validation->set_rules('password','Password','required');
         // 
            if($this->form_validation->run () == true){
                echo 'Form Validate';
                $data = array(
                    'username'=>$_POST['username'],
                    'email'=>$_POST['email'],
                    'password'=>strtoupper(hash('whirlpool',$_POST['password']))
                    );
                $this->db->insert('accounts',$data);
                $this->session->set_flashdata('success_msg', 'Sua conta foi criada com sucesso.');
                redirect("painel/register");
            }
        }
How can I send a welcome email with the registration system?