create user access in Ruby on Rails

I am a newbie at Web Development and Ruby on Rails.

For now I am building my website with login and signup features, later on I need to implement access control on the users, e.g. Super admin, System admin, sub admin, read only user access etc.

Please refer me some links or guide as to how shall i implement that.

Secondly, are there any security tools in Ruby on Rails?

Are there any other frameworks other than "brew"? If yes, then what is the difference

Thanks.

P.S. I know my question are of a very very basic level, but I really need to build my understanding in this area.