add foundation queueable trait

Author: taylorotwell

src/Illuminate/Foundation/Queue/Queueable.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Illuminate\Foundation\Queue;
+
+use Illuminate\Bus\Queueable as QueueableByBus;
+use Illuminate\Foundation\Bus\Dispatchable;
+use Illuminate\Queue\InteractsWithQueue;
+use Illuminate\Queue\SerializesModels;
+
+trait Queueable
+{
+    use Dispatchable, InteractsWithQueue, QueueableByBus, SerializesModels;
+}