There are various ways of approaching this, depending on your exact requirements. For example, you could create a table of functionalities that require access control, e.g.,
id | name
---+--------
1 | news
2 | members
3 | forum
and then create a join table for the permissions granted, e.g.,
member_id | functionality_id | access
----------+------------------+-------
1 | 1 | 1 (member #1 can read the news)
2 | 1 | 2 (member #2 can read and update the news)
2 | 2 | 2 (member #2 can read and update the member list)
