first draft

app/Resources/views/form/fields.html.twig

@@ -0,0 +1,19 @@
+{#
+   Each field type is rendered by a template fragment, which is determined
+   by the name of your form type class (DateTimePickerType -> date_time_picker)
+   and the suffix "_widget". This can be controlled by overriding getBlockPrefix()
+   in DateTimePickerType.
+
+   See http://symfony.com/doc/current/cookbook/form/create_custom_field_type.html#creating-a-template-for-the-field
+#}
+
+{% block date_time_picker_widget %}
+    {% spaceless %}
+        <div class="input-group date" data-toggle="datetimepicker">
+            {{ block('datetime_widget') }}
+            <span class="input-group-addon">
+                <span class="fa fa-calendar"></span>
+            </span>
+        </div>
+    {% endspaceless %}
+{% endblock %}