Paging in Ext Grid

Hi I am using Ext Js version 4.1.8 and I want to add paging on my extjs grid.

I have been using

Code:

Ext.create('Ext.data.Store', {
        model: 'List',    
    proxy:{
        type: 'ajax',
        api:{
            read:'getJson.php',
        },
        extraParams:{
            PRKEY : selectedProjId
        },
    },
    reader:{
        type: 'json',
        root: 'data',    
    }
});

That is working fine, but if I change my json format in my php file and change the root type to someother string like 'users' I do not see any data

Here is my json creation code in getJson.php

Code:

//in a loop
$aNode = array( 
    "Name" => "My Name",
        "ID"   => "123");
array_push($nodeArr, $aNode);
//end of loop

$json = new Services_JSON;
$jsonResult = array(
        'success' => "true",
        'users' => $nodeArr
);
echo json_encode($jsonResult );

Please help so I can add totalProperty in reader of my store and perform paging



Paging in Ext Grid