docs: def init_publisher(app):
      """Calling this with your flask app as argument is required for the
      publisher decorator to work.
  
      """
      @app.context_processor
      def inject_links():
          return {
              'websub_self_url': stack.top.websub_self_url,
              'websub_hub_url': stack.top.websub_hub_url,
              'websub_self_link': stack.top.websub_self_link,
              'websub_hub_link': stack.top.websub_hub_link,
          }