Koel is a personal music streaming server which permits to stream your downloaded music directly from your server. It’s a spotify-like and seems to be one of the best self-hosted app to listen your music (with Sonerezh).
Currently there is no official mobile client (I believe) to use it with offline-mode on your phone but you can listen music from any mobile browser (tested with Google Chrome).
Documentation : http://koel.phanan.net/#install
Currently I did the automatic installation script (installpackage-koel) and it works well on Ubuntu 16.04. If some of you shows interest in this application, I could create the other files needed to integrate Koel easily into your Quickboxes (removepackage, apache conf and dashboard web service management as it can be started/stopped).
Does some of you are interested ?