Fixes and cleanup for user pending/registration calls

app/Mail/UserPending.php

@@ -3,30 +3,27 @@
 namespace App\Mail;
 
 use App\Models\User;
-use Illuminate\Bus\Queueable;
 use Illuminate\Mail\Mailable;
+use Illuminate\Bus\Queueable;
 use Illuminate\Queue\SerializesModels;
-use Illuminate\Contracts\Queue\ShouldQueue;
 
 class UserPending extends Mailable
 {
     use Queueable, SerializesModels;
 
-    private $user;
+    private $subject,
+            $user;
 
-    public function __construct(User $user)
+    public function __construct(User $user, $subject=null)
     {
+        $this->subject = $subject ?: 'Your registration is pending!';
         $this->user = $user;
     }
 
-    /**
-     * Build the message.
-     *
-     * @return $this
-     */
     public function build()
     {
         return $this->markdown('emails.user.pending')
+                    ->subject($this->subject)
                     ->with(['user' => $this->user]);
     }
 }