Se agrega un placeholder para informar sobre la ruta al base.

src/StatsBundle/Admin/DeviceServerAdmin.php

@@ -56,6 +56,7 @@ class DeviceServerAdmin extends BaseAdmin
                 ->add('name')
                 ->add('url', TextType::class, array(
                     'help' => $this->trans('help.url'),
+                    'attr' => array('placeholder' => 'https://base.xx.flowdat.com/api/routes')
                 ))
                 ->add('saveHistoric', null, array(
                     'help' => $this->trans('help.saveHistoric'),