url: "MyApp/index.php/app/user"    or
url: "MyApp/index.php/app/user/id/(xxx)"

$(document).ready(function(){
var Item = Backbone.Model.extend({

defaults: {
  title: "Hello World!!!"
},

url: "MyApp/index.php/app/user"

});
var item=new Item;
item.save();

function user_post()
{
    $data=array(
    'id'=> NULL,
    'title'=>$this->post('title')
    );

    $result = $this->App_Model->create($data);
}

function create($data)
{

    $query = $this->db->insert('data', $data)
}

$this->post('title')

$this->input->post('title')

$this->request->body