angularjs bootstrap multiple button model value

just started with angularjs and bootstrap. Got a sample to display buttons.

             <div ng-controller="ButtonsCtrl">
                  <h4>Checkbox</h4>
                  <pre>{{checkModel}}</pre>
                  <div>
                      <button type="button" class="btn btn-primary" ng-click="checkModel.KateSpade = true" btn-checkbox>Kate Spade</label>
                      <button type="button" class="btn btn-primary" ng-model="checkModel.LouisVuitton" btn-checkbox>LouisVuitton</label>
                      <button type="button" class="btn btn-primary" ng-model="checkModel.Burberry" btn-checkbox>Burberry</label>
                      <button type="button" class="btn btn-primary" ng-model="checkModel.CalvinKlien" btn-checkbox>Calvin Klien</label>
                      <button type="button" class="btn btn-primary" ng-model="checkModel.Forever21" btn-checkbox>Forever 21</label>
                  </div>
             </div>

How do I update the values of ng-model on click. My controller looks standard.

    app.controller('ButtonsCtrl', function($scope){
        console.log("ButtonsCtrl started");

        $scope.checkModel = {
            KateSpade: false,
            LouisVuitton: true,
            Burberry: false,
            CalvinKlien: false,
            Forever21: false
        };

   });