Unless you got other sources or information, I tried the steps in above link but many packages don't exist anymore that are mentioned there. I cannot get passenger_root command running etc, to be honest my setup now is really not working or useful. It's mainly the application redmine part that is not working the webserver and redmine, not the postgres part.
That's why i come up with a high level question , how to start, who can help me.
I tried gitlab for example and that's very clear, very well documented.
Never used Passenger with NGINX, only Apache. With Apache you actually have to load the passenger module, I suspect you have to do the same with NGINX. Failing to load the module on Apache would present the exact same error message.