Dynamic root_url based on the user being logged or not

routes.rb

root :to => "home#show",    :constraints => UserLoggedConstraint.new(false)
root :to => "profile#show", :constraints => UserLoggedConstraint.new(true)

user_logged_constraint.rb

class UserLoggedConstraint
  def initialize(logged)
    @logged = logged
  end

  def matches? request
    request.session[:user_id].present? == @logged
  end
end