dns and https setup for (www.)borgbackup.org

[ThomasWaldmann]

DNS zone borgbackup.org:

@ IN A <IP from dig borgbackup.github.io>
www IN CNAME borgbackup.github.io.

Notes:

• first entry: CNAME does not work for @ thus one needs to lookup the IP(s) used by github and configure same IP(s) as A record(s) in DNS.
• second entry: github complains "incorrectly configured" if not like shown.

Github repo settings for borgbackup/borgbackup.github.io:

Custom domain: www.borgbackup.org

Notes:

• it is not possible to fill in multiple values in the form field, like:
  www.borgbackup.org borgbackup.org
• we used www.borgbackup.org - that redirects b.o --> www.b.o, which is wanted.
• if one used borgbackup.org, it would redirect like: www.b.o --> b.o

X Enforce https

Notes:

• this will fetch a letsencrypt cert
• sadly, it is only for www.borgbackup.org and not also for borgbackup.org, so the latter will have a mismatching cert.