at the end of the day, it was inevitable

src/AppBundle/DependencyInjection/AppExtension.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace AppBundle\DependencyInjection;
+
+use Symfony\Component\Config\FileLocator;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Extension\Extension;
+use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;
+
+/**
+ * Class AppExtension
+ * @package ApiDocBundle\DependencyInjection
+ */
+class AppExtension extends Extension
+{
+
+    /**
+     * Loads a specific configuration.
+     *
+     * @param array            $configs   An array of configuration values.
+     * @param ContainerBuilder $container A ContainerBuilder instance.
+     *
+     * @throws \InvalidArgumentException When provided tag is not defined in
+     *                                   this extension.
+     *
+     * @return void
+     *
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
+     */
+    public function load(array $configs, ContainerBuilder $container)
+    {
+        $loader = new YamlFileLoader(
+            $container,
+            new FileLocator(__DIR__.'/../Resources/config')
+        );
+
+        $environment = $container->getParameter('kernel.environment');
+        if ($environment === 'prod') {
+            //
+            // Inject NelmioApiDocBundle form extensions 'cause we don't load full
+            // nelmio configuration on production and we got error.
+            //
+            $loader->load('nelmio_form.yml');
+        }
+
+        $loader->load('services.yml');
+    }
+}