diff --git a/src/Models/CartModel.php b/src/Models/CartModel.php
index 5ccdec1..aa29d32 100644
--- a/src/Models/CartModel.php
+++ b/src/Models/CartModel.php
@@ -24,6 +24,7 @@ class CartModel extends Model
     protected $fillable = [
       'identifier',
       'instance',
+      'discount_rate'
     ];
   
     /**