Just to highlight - this is in no way related to the existing Apache Phoenix project, or to the ten other tech projects also called Phoenix. (https://en.wikipedia.org/wiki/Phoenix#Computing)
This is a new one.
Well, relatively new. It was actually the one I was expecting when I clicked through (the Erlang/Elixir web framework). Give it had websockets in the title, I would have been surprised if it wasn't.
I'm surprised that any hacker news reader would actually think anything else, given how often this particular Phoenix has surfaced here.