add a new property in ng-model object after it's been changed via ng-repeat

Question

I wanted to add a property "discountRate" to ng-model object after the object is changed within a ng-repeat block.

Example 1

Example 2

After selecting an option the ng-model is updated as expected. But the "discountRate" is not added as a property. Appearantly I am missing something about "scope". Would someone look into this, how can I have "discountRate" property be added to ng-model?

<form class="form-horizontal" ng-submit="addToInvoice()">
    <div class="form-group">
        <label for="inputService" class="col-sm-2 control-label">Service</label>
        <div class="col-sm-4">
            <select name="data.itemToSave" class="form-control" required="required"
                    ng-options="option.title for option in items.services track by option.id"
                    ng-model="data.itemToSave"></select>
        </div>
    </div>

    <div class="form-group">
        <label for="inputPrice" class="col-sm-2 control-label">Discount</label>

        <div class="readonly" data-toggle="buttons">
            <label class="btn btn-default" ng-class="{active: '!data.itemToSave.discountRate'}">
                <input type="radio" ng-model="data.itemToSave['discountRate']" value="0">0%</label>

            <label class="btn btn-default">
                <input type="radio" ng-model="data.itemToSave['discountRate']" value="10">10%</label>

            <label class="btn btn-default">
                <input type="radio" ng-model="data.itemToSave['discountRate']" value="20">20%</label>
        </div>


    </div>
    <div class="form-group">
        <div class="col-sm-offset-2 col-sm-4">
            <button type="submit" class="btn btn-default">Add to Invoice</button>
        </div>
    </div>
</form>

Answer 1

Removing data-toggle="buttons" makes it working, with or without ui.bootstrap

ng-change,ng-click don't work with data-toggle="buttons" since v1.3.0

https://github.com/angular/angular.js/issues/4516