Included: alert the active user someone is waiting for the item

app/Mail/UserWaiting.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Mail;
+
+use \App\Item;
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Queue\SerializesModels;
+use Illuminate\Contracts\Queue\ShouldQueue;
+
+class UserWaiting extends Mailable
+{
+    public $item;
+    public $waitingUser;
+    public $userWithItem; 
+    use Queueable, SerializesModels;
+
+    /**
+     * Create a new message instance.
+     *
+     * @return void
+     */
+    public function __construct($waitingUser, $userWithItem, Item $item)
+    {
+        $this->item = $item;
+        $this->waitingUser = $waitingUser;
+        $this->userWithItem = $userWithItem;
+    }
+
+    /**
+     * Build the message.
+     *
+     * @return $this
+     */
+    public function build()
+    {
+        return $this->subject($this->waitingUser . ' wants to use ' . $this->item->name)
+            ->markdown('emails.userWaiting');
+    }
+}