- Created `Dockerfile` for nginx;
- Downloading `options-ssl-nginx.conf` and `ssl-dhparams.pem` during
  docker build phase;
- Relevant part in the `app.conf` updated;
- Creating temp SSL certificate through `docker-entrypoint.sh` when
  nginx service is starting;

- certbot container waiting for healthy nginx container;
- during startup of the nginx container:
    - an initial certificate get created;
    - it starts nginx daemon and await for the certbot container, then
      removing temporally certificate;
    - it does start a "API" that allow certbot to reload nginx daemon;
-

… instruction