Summary: A user asked for some instructions, so I wrote up some documentation.
Test Plan: Read document. This is more or less how secure.phabricator.com backups work and the one time we had a data loss issue restoration worked reasonably well.
Reviewers: btrahan, vrana
Reviewed By: vrana
CC: aran
Differential Revision: https://secure.phabricator.com/D3825
