DependencyInjection/Configuration.php
private function addDoctrineSection(ArrayNodeDefinition $rootNode)
    {
        $rootNode
            ->children()
                ->arrayNode('doctrine')
                    ->info('doctrine configuration')
                    ->canBeEnabled()
                    ->children()
                        ->booleanNode('enabled')->defaultTrue()->end()
                    ->end()
                ->end()
            ->end()
        ;
    }
private function addDoctrineSection(ArrayNodeDefinition $rootNode)
    {
        $rootNode
            ->children()
                ->arrayNode('doctrine')
                    ->info('doctrine configuration')
                    ->canBeEnabled()
                    ->children()
                        ->booleanNode('enabled')->defaultTrue()->end()
                    ->end()
                ->end()
            ->end()
        ;
    }
Add doctrine section.

@param ArrayNodeDefinition $rootNode