add command to keep the ansible container running

Author: amandayclee

docker-compose.yml

@@ -9,4 +9,5 @@ services:
       dockerfile: ansible/Dockerfile
     volumes:
       - ./config/ansible.cfg:/etc/ansible/ansible.cfg
-      - ./config/hosts:/etc/ansible/hosts
+      - ./config/hosts:/etc/ansible/hosts
+    command: sh -c 'trap "exit" TERM; while true; do sleep 1; done'