Angular directive with data- attribute & controller

HTML

<div ng-app="zippyModule">
  <div ng-controller="Ctrl3">
    Title: <input ng-model="title">
    <hr>
    <div data-zippy="zippy" zippy-title="title"></div>
  </div>
</div>

JavaScript

function Ctrl3($scope) {
  $scope.title = 'Lorem Ipsum';
}

angular.module('zippyModule', [])

.directive('zippy', function(){
    return {
        restrict: 'A',
        replace: true,
        scope: { title:'=zippyTitle' },
        controller: 'ZippyCtrl', 
        template: '<input type="text" ng-model="title"style="width: 90%"/>',
        link: function(scope, element, attrs, ctrl) {
            alert(scope.title);
        }
    }
}).

controller('ZippyCtrl', ['$scope', function($scope) {
  var self = $scope;
  
  return self;
}]);