Clarify And/Or Document Apex Setting about haiku9 HOT 1 OPEN

Further comments by @freeformflow on Slack:

we issue subdomains for pandastrike projects. www.pandastrike.com, foo.pandastrike.com bar.pandastrike.com etc But Dan wanted a way to assign just pandastrike.com to something. In the config, there array of hostnames for [www, foo, bar], but it's hard to describe the absence of something. Furthermore, should pandastirke.com route to www.pandastrike.com? or the other way around?

These problems gave rise to the apex field. It can either be:

1. primary (everything goes to pandastrike.com) or
2. secondary (everything goes to the first in the hostname list, in this case www)
3. you can omit the apex field entirely and nothing is done to the pandastrike.com DNS record

In the blurb9 project, the reason we included apex is because that project has its own root domain, separate from pandastrike.com.

from haiku9.