Ability Class

ability.rb

class Ability
  include CanCan::Ability

  class_attribute :permissions

  attr_reader :user

  def initialize(user)
    @user = user
    apply_permissions
  end

  private

  def apply_permissions
    if permissions.respond_to?(:call)
      permissions.call(self)
    else
      instance_eval(permissions)
    end
  end

end