How to override server time in config.php codeigniter

Question

I want to know how to override server time , my server is in UK but my Client is in Singapore and he wants Singapore time. in php.ini date.timezone is Europe/London which i do not want to change. i want to handle from config.php i tried this in codeigniter config.php

$config['time_diff']= "+8";
$config['time_reference'] = 'gmt';
date_default_timezone_set('UTC');

i also even tried this

$config['time_reference'] = 'local';
date_default_timezone_set('Singapore');

Answer 1

Within config.php

<?php

if (!defined('BASEPATH'))
    exit('No direct script access allowed');

if (!defined('DS')) {
    define('DS', DIRECTORY_SEPARATOR);
}

date_default_timezone_set('Asia/Singapore');