I have marked this as experimental because I haven't put an awful amount of time into it. It needs more use to confirm its suitable for others needs.
A simple Casbin BoltDB Adapter (see https://casbin.org/docs/en/adapters). This flavour supports the auto-save functionality.
Right now it supports the autosave functionality, and I've worked in some restricted filtered adapter functionality - difficult with a simple k/v store like Bolt.
Individual policy lines get saved into the specified BoltDB bucket which is keyed using a :: delimited value of the
role. The value content is a JSON representation of the policy rule.