agora.yml format - include/exclude and home node

My agora.yml contains an include/exclude list to be applied to the markdown files in my repo. I've modelled it on Jekyll-style files of the same type, and here was my original suggestion:

exclude:
- _posts/journal/*
- _posts/archive/*
include:
- _posts/journal/2021-01-24-journal.md

I'm going to link back to these issues from my Anagora node.

My live agora.yml in my repo has a much longer list of excludes, plus a meta rule:

Unless in the include section, any file without a .html or .md extension is excluded, as are directories that begin with a period (.).

Looking at that again, probably adding some common image formats like .png, .svg, .jpg etc should be added too.

Also, rather than an index file that may only make sense when published as a standalone web page, I've suggested a home key with a path to a Markdown file:

home: _notes/agora.md