I followed much of tessus Apache-config description found in the post you provided the link to… Can I reverse-proxy the server into a sub-location? - #4 by tessus
Of course there were some implied config steps needed in addition to what is stated there. Like e.g. create an atuin user and group… set the correct permissions for the files and directories mentioned… create the /var/log/atuin directory etc. I am glad I know my ways around web-server stuff a bit. This does not come as naturally to me as gfx-hacking 
Hm… I did all that.
When I log into the text-based interface of PostgreSQL and do a…
select distinct hostname from history;
… I only see one entry… some encrypted hostname-string I assume. I would have expected to see three different rows in the result from the select-statement, since I have three client-machines I sync from.
Best regards…
MacSlow