gistfile1.rb

## From the cancan home page
  class Ability
    include CanCan::Ability

    def initialize(user)
      if user.admin?
        can :manage, :all
      else
        can :read, :all
      end
    end
  end

## database-driven
  class Ability
    include CanCan::Ability

    def initialize(user)
      permission = Permission.find_by_level(user.level)
      permission.allowed_actons do |action|
        can action.to_sym, :all
      end
    end
  end