Add Nu Game Engine (#444)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -318,6 +318,7 @@ _Set of game frameworks, engines and platforms_
 - :tada: [Nakama](https://github.com/heroiclabs/nakama) - Distributed server for social and realtime games and apps.
 - :tada: [nCine](https://ncine.github.io/) - A cross-platform 2D game engine with an emphasis on performance, written in C++11 and optionally scriptable in Lua.
 - :free: [NodeBox](https://www.nodebox.net/) - a family of Python tools to create generative design.
+- :money_with_wings: [Nu Game Engine](https://github.com/bryanedds/Nu) - Functional 2D/3D game engine in F# (free for noncommercial use; paid commercial license).
 - :tada: [nuklear](https://github.com/Immediate-Mode-UI/Nuklear) - A single-header ANSI C immediate mode cross-platform GUI library.
 - :tada: [ÖbEngine](https://github.com/Sygmei/ObEngine) - 2D Game Engine with Lua Scripting made on top of SFML !
 - :tada: [ODE](http://www.ode.org/) - ODE is an open source, high performance library for simulating rigid body dynamics.