Add guzzle events to customize.md

Author: cursedcoder

doc/customize.md

@@ -11,6 +11,25 @@ $client->getHttpClient()->setOption('user_agent', 'My new User Agent');
 
 See all available options in `Github/HttpClient/HttpClient.php`
 
+### Guzzle events
+
+If you need to perform any special action on request/response use guzzle events:
+
+```php
+use Guzzle\Common\Event;
+use Github\HttpClient\Message\ResponseMediator;
+
+$client->getHttpClient()->addListener('request.success', function(Event $event) {
+   $remaining = ResponseMediator::getApiLimit($event['response']);
+
+    var_dump($remaining);
+});
+
+$client->user()->show('cursedcoder');
+```
+
+see list of events http://guzzle3.readthedocs.org/http-client/request.html#plugins-and-events
+
 ### Inject a new http client instance
 
 `php-github-api` provides a curl-based implementation of a http client.