The systemd units are pushed here https://salsa.debian.org/ruby-team/diaspora-installer/-/commit/c40f18f363a35a967690e8bbff382330638b2755
We currently use debhelper compat 10 for this (like gitlab), but we need to find out how to do it in newer debhelper compat versions.
Another thing is we need to properly manage /etc/diaspora.conf migration to /etc/diaspora/diaspora.conf and find a way to export these variables for the init script (gitlab does that already and we can use the same strategy here).