code: public function getConfigTreeBuilder()
      {
          $treeBuilder = new TreeBuilder();
          $rootNode = $treeBuilder->root('jb_phumbor');
  
          $rootNode
              ->children()
                  ->arrayNode('server')
                      ->addDefaultsIfNotSet()
                      ->children()
                          ->scalarNode('url')
                              ->defaultValue('http://localhost:8888')
                          ->end()
                          ->scalarNode('secret')
                              ->defaultValue('')
                          ->end()
                      ->end()
                  ->end()
              ->end();
  
          $this->addTransformationSection($rootNode);
  
          return $treeBuilder;
      }
docs: Generates the configuration tree builder.
  
  @return TreeBuilder The tree builder