Added documentation on the LoggingDecorator and Dummy class

Author: hannesvdvreken

README.md

@@ -83,15 +83,31 @@ $twilio->call('+18085551212', function ($message) {
 });
 ```
 
-Generating TwiML:
+#### Dummy class
 
-```php
-$twiml = $twilio->twiml(function($message) {
-    $message->say('Hello');
-    $message->play('https://api.twilio.com/cowbell.mp3', array('loop' => 5));
-});
+There is a dummy implementation of the `TwilioInterface` available: `Aloha\Twilio\Dummy`. This class
+allows you to inject this instead of a working implementation in case you need to run quick integration tests.
+
+#### Logging decorator
 
-print $twiml;
+There is one more class available for you: the `Aloha\Twilio\LoggingDecorator`. This class wraps any
+`TwilioInterface` object and logs whatever Twilio will do for you. It also takes a `Psr\Log\LoggerInterface` object
+(like Monolog) for logging, you know.
+
+By default the service providers don't wrap objects with the `LoggingDecorator`,
+but it is at your disposal in case you want it. A possible use case is to construct a
+`TwilioInterface` object that logs what will happen, but doesn't actually call Twilio (using the Dummy class):
+
+```php
+if (getenv('APP_ENV') === 'production') {
+    $twilio = $container->make(\Aloha\Twilio\Manager::class);
+} else {
+    $psrLogger = $container->make(\Psr\Log\LoggerInterface::class);
+    $twilio = new LoggingDecorator($psrLogger, new \Aloha\Twilio\Dummy());
+}
+
+// Inject it wherever you want.
+$notifier = new Notifier($twilio);
 ```
 
 ### License