add nova

nova/src/Contracts/Downloadable.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Laravel\Nova\Contracts;
+
+/**
+ * @method \Illuminate\Http\Response toDownloadResponse(\Laravel\Nova\Http\Requests\NovaRequest $request, \Laravel\Nova\Resource $resource)
+ *
+ * @mixin \Laravel\Nova\Fields\Field
+ */
+interface Downloadable
+{
+    //
+}