Ask HN: LEMP-friendly project management software

Hello. I'm looking for a project management tool akin to OpenProject that I can self-host and use on a small scale (sub-10 users). I have not yet tried OpenProject in real life because I'm waiting patiently for Ubuntu 18.04 support, which is coming.

While I wait, I would like to look at alternatives with a view to ongoing use and offering something back to the community in some fashion, whether it's documentation, user support or something else.

I'm running a Linux, Nginx, MySQL (Persona) and PHP stack and something that fits nicely into that setup would be super. I do web ops by day, so I'm well-versed with the technicals. Until now, however, I've used only proprietary desktop software.

What would you recommend I look at, and also avoid? Any advice is very warmly received. Thanks very much in advance.