PERM is: a framework that supports a lot of access-control models
    github:https://github.com/casbin/casbin
    docs:https://casbin.org/docs/zh-CN/overview

    • Concept of “PERM (Policy, Effect, Request, Matcher)”:
      • Policy - defines everything
      • Effect - the result of Policy
      • Request - who want to do want
      • Matcher - decides is request fulfills policy
    • We define policy in .conf, and instances in .csv
      • There are functions to add, set, remove those policies or instances from outside (Casbin API)