Fix error on registration page (oops).

src/Users/User.php

@@ -1,10 +1,13 @@
 <?php
 namespace Misuzu\Users;
 
+use Illuminate\Database\Eloquent\SoftDeletes;
 use Misuzu\Model;
 
 class User extends Model
 {
+    use SoftDeletes;
+
     protected $primaryKey = 'user_id';
 
     public function sessions()