Make sorting of invoice items reliable.

app/Models/Invoice.php

@@ -104,7 +104,7 @@ class Invoice extends Model
      */
     public function items(): HasMany
     {
-        return $this->hasMany(Invoiceitem::class);
+        return $this->hasMany(Invoiceitem::class)->orderBy('sort');
     }
 
     /**

app/Models/Invoiceitem.php

@@ -22,6 +22,7 @@ class Invoiceitem extends Model
         'total',
         'name',
         'description',
+        'sort'
     ];
 
 }