Basic integration of [Casbin-RS](https://github.com/casbin/casbin-rs) with [RBAC](https://en.wikipedia.org/wiki/Role-based_access_control) for Actix Web.
In this example, you can get the successful result at `http://localhost:8080/success` (accessible) and the failed result at `http://localhost:8080/fail` (inaccessible, `ERR_EMPTY_RESPONSE`).