CanDo is a small gem to implement a simple user access system based on users, roles & capabilites, where: each user can have 0, 1 or many roles each role can have 0, 1 or many capabilites Users have capabilities by getting roles assigned (role == collection of capabilities). Within the code, the can helper method can be used to test whether a user has a certain capability or not (see below for a working code example).