added email subscriptions

app/Models/SentEmail.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Str;
+
+class SentEmail extends Model
+{
+    protected $fillable = ['recipient', 'mailable_class'];
+    public $incrementing = false;
+    protected $keyType = 'string';
+
+    /**
+     * Boot function from Laravel.
+     *
+     * @return void
+     */
+    protected static function boot(): void
+    {
+        parent::boot();
+
+        static::creating(function ($model) {
+            if (empty($model->{$model->getKeyName()}) === true) {
+                $model->{$model->getKeyName()} = strtolower(Str::random(15));
+            }
+        });
+    }
+}