Angular Timer countdown reset countdown

<!DOCTYPE html>
<html>
  <head>
  <script src="http://siddii.github.io/angular-timer/bower_components/jquery/jquery.min.js"></script>
  <script src="http://siddii.github.io/angular-timer/bower_components/angular/angular.min.js"></script>
  <script src="http://siddii.github.io/angular-timer/dist/angular-timer.min.js"></script>
  
  <script type="text/javascript">
    angular.module('timer-demo',['timer']).controller('TimerDemoController',['$scope',  function ($scope) {
      $scope.startTime = new Date().getTime() +  180*60*1000;
      $scope.countdown = 180*60;
      
      $scope.resetTimer = function() {
        $scope.countdown = 180*60;
      };
      
    }]);
    
  </script>
  </head>

  <body ng-app="timer-demo" ng-controller="TimerDemoController">
    <timer start-time="startTime" interval="1000" countdown="countdown">{{seconds}} seconds.</timer>
    <div><button ng-click="resetTimer()">Reset countdown</button></div>
  </body>

</html>