code: def add_to_manifest(self, manifest):
          
          # Add this service to list of services
          manifest.add_service(self.service.name)
  
          # Add environment variables
          zone_id = predix.config.get_env_key(self.use_class, 'zone_id')
          manifest.add_env_var(zone_id,
                  self.service.settings.data['zone']['http-header-value'])
  
          uri = predix.config.get_env_key(self.use_class, 'uri')
          manifest.add_env_var(uri, self.service.settings.data['uri'])
  
          manifest.write_manifest()
docs: Add useful details to the manifest about this service
          so that it can be used in an application.
  
          :param manifest: An predix.admin.app.Manifest object
              instance that manages reading/writing manifest config
              for a cloud foundry app.