laravel/framework — pull request #4503 by prady00 (2014-05-27 14:11:23+00:00)
Title: Fixes #4127

To add validation rule for php timezones

```php
protected function validateTimezone($attribute, $value)
{
try {
new DateTimeZone($value);
}catch (Exception $e){
return false;
}
return true;
}
```