Log for nonsensical configs

src/github.com/matrix-org/go-neb/services/github/github.go

@@ -224,7 +224,11 @@ func (s *githubService) PostRegister(oldService types.Service) {
 	// PostRegister handles creating/destroying webhooks, which is only valid if this service
 	// is configured on behalf of a client.
 	if s.ClientUserID == "" {
-		// TODO: We should log an error here if the service has any webhook config in Rooms
+		if len(s.Rooms) != 0 {
+			log.WithFields(log.Fields{
+				"Rooms": s.Rooms,
+			}).Error("Empty ClientUserID but a webhook config was supplied.")
+		}
 		return
 	}