AD1641/mybackend ? reverse-engineered prompt

Build me a simple backend server in C++ that can handle basic HTTP requests, route different paths, and send text or JSON responses.

I want it to act like a tiny API framework, with routes defined in one place, support for GET, POST, PATCH, and DELETE, and route params like /users/:id. Please include an in memory data store that keeps data while the server is running, then resets when the server restarts. A small example API for managing users would be perfect, with list, create, update, and delete routes.

Make it easy to build and run with CMake, and include a simple way to test requests manually from the command line. If you need to check current CMake or C++ docs online, feel free to do that.