R1:74e39bfe41be

Provide basic documentation about Aphlict

Summary: Hopefully this is helpful? Also fixed a thing that wasn't using config.

Test Plan: Read documentation. Sent myself a notification over the server.

Reviewers: jungejason

Reviewed By: jungejason

CC: aran

Maniphest Tasks: T944

Differential Revision: https://secure.phabricator.com/D2804