A simple example, using Actix web, diesel-adapter and Postgresql.
You need to have docker and docker-compose commands installed.
Run make to setup and run the application.
Then open http://127.0.0.1:1080/?name=casbin, it should say OK which can mean you have access!
If you change the name to anything else, it would return a 403 response with Forbidden message.