fix mailing an email

app/Models/Diocesi.php

@@ -3,15 +3,15 @@
 namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
-use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 
 class Diocesi extends Model
 {
     protected $table = 'diocesi';
     protected $fillable = ['nome', 'regione'];
 
-    public function gruppi(): HasMany
+    public function gruppi(): BelongsToMany
     {
-        return $this->hasMany(Gruppo::class);
+        return $this->belongsToMany(Gruppo::class, 'diocesi_gruppo');
     }
 }