add code to extract all resolving domains from the containers

Dockerfile

@@ -9,13 +9,15 @@ RUN apt-get update; \
     git clone https://github.com/letsencrypt/letsencrypt ;\
     cd /letsencrypt ;\
     ./letsencrypt-auto --help
+RUN pip3 install docker-py
 
 ADD haproxy_ssl.conf /haproxy_ssl.conf
 ADD haproxy.conf /haproxy.conf
 ADD letencrypt.conf /letencrypt.conf
 
 ADD start.py /start.py
-RUN chmod +x /start.py
+ADD list_domains.py /list_domains.py
+RUN chmod +x /*.py
 
 VOLUME ["/data"]