This does more than explain how to save a new forge in production/staging. This needs to
be evolved to also explain how to run it through docker (in another diff).
Maybe that should move in the new sysadm sphinx instance we talked
about a while back though.
(I put it there without thinking too much about it since I want to iterate over this
to add or rework the add an instance for listing a section)
thoughts?
Related to T3629