$ gem install cancan-sugar

gem "cancan-sugar"

class Ability
  include CanCan::Ability

  def initialize(user)
    user ||= User.new

    permissions_for user, as: :admin do
      can :manage, :all
    end

    permissions_for user, as: [:manager, :user] do
      can :update, User, id: user.id
      can :read, Document
      can :update, Document, user_id: user.id
      can :create, Document
    end
    
    permissions_for user, as: :manager do
      can :comment, Document
      can :create, Comment
      can :create, DocumentComment
      can :create, Incedent
      can :update, Incedent, initiator_id: user.id
    end

  end
end