User permissions on main site

Dat

I want to be able to set permissions for a user on what they can see on the main site.

So if a user has permission to a page called "Grades" they can see it. (ie. a teacher can only see it)

Is there a way I can do this? like (just an example in thoughts)
if($user->permissions('grades')){ echo 'page'; }else{ echo 'only teachers allowed'; }

admin

The fuel_users table is specific to logging into FUEL CMS and so any type of front end permissions would probably want to be done in a separate table/model. You could then create a controller (the normal CI way) to handle authentication. If you would like to manage those users you could create a module that's associated with that model:
http://www.getfuelcms.com/user_guide/modules/simple