UBOS user Emmanual Arthur wrote us with this experience report. You can often find him on #ubos.
Let’s say you have set up a site with one app (e.g. owncloud), as it is described in Setting up your first web app. What if you’d like to run a second app at the same site, say selfoss?
Our friends at ownCloud released their version 8 the day before we pushed out UBOS beta 2. We managed to include it at the last minute, and here is a video that shows how easy it is to install ownCloud on UBOS.