def store_page(page)
      return true if page.nil?
      unless touchable_pages.include? page
        touchable_pages << page
        save
      end
    end
def store_page(page)
      return true if page.nil?
      unless touchable_pages.include? page
        touchable_pages << page
        save
      end
    end
Stores the page into +touchable_pages+ (Pages that have to be touched after updating the element).