Full permission for everyone on a special table

I wanted to setup a table (audit) inside “mysql” database, with full permissions available to anyone, and including those users that I may create in the future too.
How should I create this tble (mysql.audit) so that everyone can access?

Basically, it will make use of “init_connect” string to log who has logged into the mysql.
Any user should have INSERT permission on this table, by default.

Any luck?