diff --git a/config/sample.yml b/config/sample.yml
index 81d292a84..a70067a31 100644
--- a/config/sample.yml
+++ b/config/sample.yml
@@ -15,6 +15,7 @@ nexmo:
   number:
 
 gcm:
+  senderId:
   apiKey: 
 
 # Optional. Only if iOS clients are supported.