add material price setter

api/models/product.py

@@ -41,6 +41,11 @@ class Material(db.Model):
             return float(self.material_price.price)
         return None
 
+    @price.setter
+    def price(self, value):
+        if self.material_price:
+            self.material_price.price = value
+
     def to_json(self):
         return {
             'id': self.id,