Add installation instructions for Symfony bundle

Author: tacman

README.md

@@ -27,6 +27,12 @@ Install with [Composer](https://getcomposer.org/):
 
     composer require samwilson/phpflickr
 
+Symfony developers can install a [bundle](https://github.com/survos/SurvosFlickrBundle):
+
+    composer require survos/flickr-bundle
+
+After setting the API key and secret in the environment, you can simply inject the FlickrService into your controller or service, rather than instanciating it as described below.
+    
 ## Usage
 
 Once you've included Composer's autoloader, create a PhpFlickr object.