How to create a field dynamically in Ionic and / or Angular Js?

Have a list of products, but my list does not have the quantity field, and neither should have because it would be stock control and that's not it.

I want the quantity field to when I click (+) add 1 and click (-) to decrease 1.

I try to create the quantity field in the controller like this:

$scope.user.bebidasextras.quantidade=0;

And in the View this way:

<i class='icon ion-plus-round icon-plus-round' mouse-down-up ng-click='addProduct(product)'></i>
                             <span class='product-quantity'>{{bebida.quantidade}}</span>
<i class='icon ion-minus-round icon-minus-round' mouse-down-up ng-click='removeProduct(product)'></i>

But even zero (0) does not appear in my view so the user understands that the item is zeroed.

How to create this field, what will be saved after?