Merging CodeIgniter and NoNonsense Forum

OK, but I'm still no further ahead for my need of a "simple forum" and "chat system".

I've never found a production-ready discussion forum built with or for CodeIgniter. There are several tutorials that layout in a very fundamental way the skeleton of a forum. Google is your friend in finding these. There is one solution on GitHub that seems a bit more fully developed than the typical tutorial. But as it says on their GitHub page, "DON'T USE IT AS IS IN A PRODUCTION SERVER, THIS FORUM APP IS STILL IN DEVELOPMENT." [emphasis not added]  It has not had a commit for four years so it would seem development has ceased. You could take the code as a starting point for a DIY solution.

A DIY seems like a great idea until you dive in. It quickly becomes clear that you will need years to make a robust, secure and useful discussion forum. If it was easy you wouldn't see so many big name companies using third-party solutions.

You might not like the subdomain idea but it is usually the easiest and least expensive in terms of both time and money to implement. In case you haven't noticed this very forum is in a subdomain.