Add to upgrade guide.

Author: taylorotwell

upgrade.md

@@ -9,6 +9,26 @@
 <a name="upgrade-4.3"></a>
 ## Upgrading To 4.3 From 4.2
 
+## Compile Configuration File
+
+The `app/config/compile.php` configuration file should now follow the following format:
+
+	<?php
+
+	return [
+
+		'files' => [
+			//
+		],
+
+		'providers' => [
+			//
+		],
+
+	];
+
+The new `providers` option allows you to list service providers which return arrays of files from their `compiles` method.
+
 ## Beanstalk Queuing
 
 Laravel 4.3 now requires `"pda/pheanstalk": "~3.0"` instead of `"pda/pheanstalk": "~2.1"` that Laravel 4.2 required.