code: public function addConfiguration(NodeDefinition $node)
      {
          parent::addConfiguration($node);
          $node
              ->children()
                  ->scalarNode('url')->isRequired()->end()
                  ->booleanNode('is_secured')->defaultTrue()->end()
                  ->booleanNode('is_https')->defaultTrue()->end()
                  ->scalarNode('cache')->defaultNull()->end()
                  ->integerNode('cache_ttl')->defaultValue(86400)->end()
              ->end();
      }
docs: {@inheritdoc}