tour.rb

class Tour < ApplicationRecord
  # This is used when generating urls, ie. tour_path(@tour) will give you "/tours/#{@tour.to_param}"
  def to_param
    tour_id # The field name that gives you 'e4Hqh8jTTcCrvQ3kH26Mtd7a'
  end
end

I'm doing that in the tour controller

---

private
      def to_param
        token
      end
end