Update documentation

[Maxzor]

I started a bookwyrm production instance and faced two problems :

• The certbot container writes as root, and the following challenges fail.
  I solved it with
  sudo chmod -R 755 certbot
sudo chown -R [myUser]:[myGroup] certbot
• The documentation says for the SSL setup to uncomment from lines 18 to 50. In my case it was from 18 to 111, the whole SSL server block.