VOL-612 - rename images to work better with public repository

Change-Id: I9679544987c3a08d0001928cfbc39d710a6c1eae
diff --git a/unum/Makefile b/unum/Makefile
index ce8c23c..1a39029 100644
--- a/unum/Makefile
+++ b/unum/Makefile
@@ -20,7 +20,7 @@
 	@echo "  rm        - remove the sample 3 instance cluster"
 
 image:
-	docker build --rm --tag voltha/unum:latest .
+	docker build --rm --tag ${REGISTRY}${REPOSITORY}unum:${TAG} .
 
 deploy:
 	docker stack deploy -c docker-compose.yml test