def initialize(user)
    if User.find_by_username "guest" && !user
      user = User.find_by_username "guest"
    else
      user ||= User.create!(:role => "guest", :username => "guest", :email => "seivan@kth.se", :password => "secret", :password_confirmation => "secret")
    end
    if user.role? :admin
      can :manage, :all
    end

    if user.role? :moderator
      can :manage, :all
    end

    if user.role? :user
      can :read, :all
      can :create, :all
      can :destroy, :all do |all|
        all.try(:user) == user
        3.minutes.ago <= all.created_at
      end
      can :update, :all do |all|
        all.try(:user) == user
        3.minutes.ago <= all.created_at
      end
    end

    if user.role? :guest
      can :read, :all
    end