Permission rules to reference other tables

### Version Information
INFO hasura cli version=v2.20.0
Need hasura permission for reference table
### What is the current behaviour?

### First flow
- When I login as a user and try to get the user detail, I get only the login user detail which is working fine since I have added permission to the select with `X-Hasura-User-Id`
### Second flow
- Suppose other users create a post in the database.
- Now if I log in and try to fetch the user post it is fetching all the posts since there is permission is a public table. But if I try to get user detail along with the post by referencing the user table, I get null. And this is expected since user detail can only access by `X-Hasura-User-Id`.

### What is the expected behaviour?
I want to fetch the post along with the user detail without updating of setting `user table select permission`. So the question really is How to add reference table permission? like fetch post and along with that username, email and id

### Keywords
hasura, permission,graphql-engine