Create item with UID in firebase

[rafaelmoura]

I’m trying to create multiple items in the firebase list using user’s UID as we can in image bellow

this is my method to create items

  formCreate() {
    this.service.save(this.products)
        .then(() => { 
          this.navCtrl.setRoot('ProductPage');
        }) 
       ............
  }

and my service I have this code to save item in list

  save(product: Product) {
    return new Promise((resolve) => {
          firebase.database()
          .ref(`/products/`)
          .child(product.user_id)
          .set(product)
          .then(() => resolve());
    })
  }

in this way the method is replacing the item to another item and not saving multiple items, how to resolve it’s ?
I realized that “set” update item and not save…