add commented link to fix

roles/docker/templates/docker-compose.yml.j2

@@ -46,7 +46,7 @@ services:
 {% if container.ports is defined %}
     ports:
 {% for port in container.ports %}
-      - "{{ port }}"
+      - "{{ port }}" # https://github.com/go-yaml/yaml/issues/34#issuecomment-55772666
 {% endfor %}
 {% endif %}
 {% if ( container.environment is defined ) or ( container.include_global_env_vars is defined and container.include_global_env_vars) %}