Add default app ID

Author: simonhamp

config/nativephp.php

@@ -13,7 +13,7 @@
      * usually in the form of a reverse domain name.
      * For example: com.nativephp.app
      */
-    'app_id' => env('NATIVEPHP_APP_ID'),
+    'app_id' => env('NATIVEPHP_APP_ID', 'com.nativephp.app'),
 
     /**
      * If your application allows deep linking, you can specify the scheme