Under Linux, or on several Web-server installations, there exists a Web-application, which is written in PHP scripts, named “eGroupWare”. This is particularly easy to install under Debian / Linux.
Its purpose to to allow an administrative user to grant numerous non-administrative users access to tools, which allow the coordination of projects, timetables, and the booking of (any, symbolized) resources. It allows for notifications to be sent out, as well as for some socializing to take place between registered users. It also allows for its own WiKi to be created, and a custom Web-page. It is extensible through numerous apps that exist within.
Most importantly, each user has complex Access Control Lists, which control in great detail what aspects of the functioning of objects he is allowed to decide. Obviously, the main administrative user has his ACLs set to allow access to everything, including the editing of the ACLs themselves.
I have installed and started eGroupWare on this server. But my great failing in this is, that currently, I am also the only user, even though I could invite people to visit and receive accounts from me, and to collaborate through this site.
Without an actual user population, this is just a fun game to play for me, in administering my Web-site in general.
(Edit 11/05/2016 : ) It is a fact that while I was installing eGroupWare on this machine, because the same machine also hosts my blog, my blog was offline for a few minutes, around 15h08 November 3. This happened in fact, because I was making ad-hoc changes to a suggested configuration script belonging to the Debian-packaged version of eGroupWare, in hopes of making this Web-application more secure. These changes of mine prevented me from restarting the Apache server, until I edited them back out. And so, by 15h27 that same night, my server was back up.
I had assumed that nobody would notice, as this outage really only lasted a few minutes, and I was not experiencing heavy traffic at that time.
And as it turned out, there was a more-correct way to change the configuration, than the method I had been trying – to edit that file.