fixes #4 (#5)

diff --git a/docker-compose/docker-whisk-controller.env b/docker-compose/docker-whisk-controller.env
index df34852..35c8739 100644
--- a/docker-compose/docker-whisk-controller.env
+++ b/docker-compose/docker-whisk-controller.env
@@ -28,3 +28,5 @@
 
 WHISK_API_HOST=https://${DOCKER_COMPOSE_HOST}
 
+WHISK_SYSTEM_KEY=whisk.system
+