update

app/models/repayment.py

@@ -38,15 +38,13 @@ class Repayment(db.Model):
 
         repayment = cls(
             customer_id=customer_id,
-            loan_id=loan.id,
+            loan_id=loan_id,
             product_id=product_id,
         )
 
         try:
             db.session.add(repayment)
-            db.session.commit()
         except IntegrityError as err:
-            db.session.rollback()
             raise ValueError(f"Database integrity error: {err}")
 
         return repayment