adding a tester container

Change-Id: I6ca83cdbfc582daf561817e10262f8b1db85d27f
diff --git a/Makefile b/Makefile
index 055094b..6a02798 100644
--- a/Makefile
+++ b/Makefile
@@ -76,7 +76,7 @@
 
 build: protos containers
 
-containers: docker-base voltha chameleon ofagent podder netconf shovel onos
+containers: docker-base voltha chameleon ofagent podder netconf shovel onos tester
 
 docker-base:
 	docker build -t cord/voltha-base -f docker/Dockerfile.base .
@@ -102,6 +102,9 @@
 onos:
 	docker build -t cord/onos -f docker/Dockerfile.onos docker
 
+tester:
+	docker build -t cord/onos -f docker/Dockerfile.tester docker
+
 protos:
 	make -C voltha/protos
 	make -C chameleon/protos