angular.module('app', ['ui']);

angular.module('app').controller('MainCtrl', function($scope) {
  $scope.message = "Will load shortly...";
  
  /*$scope.options = {
    tags: [
      {id:4, text:'red'},
      {id:2, text:'blue'},
      {id:8, text:'white'},
      {id:41, text:'green'},
      {id:13, text:'yellow'}
    ]
  };*/
  
  $scope.tags = [8, 2];
  
  $scope.message = 'Loaded';
});

angular.element(document).ready(function() {
  angular.bootstrap(document, ['app']);
});
<!doctype html>
<html xmlns:ng="http://angularjs.org">
<head>
  <meta charset="utf-8">
  <title>AngularJS Plunker</title>
  <link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.18/themes/base/jquery-ui.css">
  <link href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css" rel="stylesheet">
  <link href="http://ivaynberg.github.com/select2/select2-3.2/select2.css" rel="stylesheet"/>
  <link rel="stylesheet" href="style.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
  <script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.18/jquery-ui.min.js"></script>
  <script src="https://raw.github.com/twitter/bootstrap/master/docs/assets/js/bootstrap.js"></script>
  <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.1/angular.js"></script>
  <script src="angular-ui.js"></script>
  <script src="http://ivaynberg.github.com/select2/select2-3.2/select2.js"></script>
  <script src="app.js"></script>
</head>
<body ng-controller="MainCtrl">
  <h4>{{message}}</h4>
  <p>
    <input type="hidden" ng-model="tags" class="input-large" ui-select2="{ tags: [{ id:5, text: 'tag1' }, { id: 8, text: 'tag2' }] }" />
  </p>
</body>
</html>

/**
 * AngularUI - The companion suite for AngularJS
 * @version v0.3.2 - 2012-12-04
 * @link http://angular-ui.github.com
 * @license MIT License, http://www.opensource.org/licenses/MIT
 */


angular.module('ui.config', []).value('ui.config', {});
angular.module('ui.filters', ['ui.config']);
angular.module('ui.directives', ['ui.config']);
angular.module('ui', ['ui.filters', 'ui.directives', 'ui.config']);

/**
 * Enhanced Select2 Dropmenus
 *
 * @AJAX Mode - When in this mode, your value will be an object (or array of objects) of the data used by Select2
 *     This change is so that you do not have to do an additional query yourself on top of Select2's own query
 * @params [options] {object} The configuration options passed to $.fn.select2(). Refer to the documentation
 */
angular.module('ui.directives').directive('uiSelect2', ['ui.config', '$http', function (uiConfig, $http) {
  var options = {};
  if (uiConfig.select2) {
    angular.extend(options, uiConfig.select2);
  }
  return {
    require: '?ngModel',
    compile: function (tElm, tAttrs) {
      var watch,
        repeatOption,
  	repeatAttr,
        isSelect = tElm.is('select'),
        isMultiple = (tAttrs.multiple !== undefined);

      // Enable watching of the options dataset if in use
      if (tElm.is('select')) {
        repeatOption = tElm.find('option[ng-repeat], option[data-ng-repeat]');

        if (repeatOption.length) {
		  repeatAttr = repeatOption.attr('ng-repeat') || repeatOption.attr('data-ng-repeat');
          watch = jQuery.trim(repeatAttr.split('|')[0]).split(' ').pop();
        }
      }

      return function (scope, elm, attrs, controller) {
        // instance-specific options
        var opts = angular.extend({}, options, scope.$eval(attrs.uiSelect2));

        if (isSelect) {
          // Use <select multiple> instead
          delete opts.multiple;
          delete opts.initSelection;
        } else if (isMultiple) {
          opts.multiple = true;
        }

        if (controller) {
          // Watch the model for programmatic changes
          controller.$render = function () {
            if (isSelect) {
              elm.select2('val', controller.$modelValue);
            } else {
              if (isMultiple && !controller.$modelValue) {
                elm.select2('data', []);
              } else {
                elm.select2('data', controller.$modelValue);
              }
            }
          };


          // Watch the options dataset for changes
          if (watch) {
            scope.$watch(watch, function (newVal, oldVal, scope) {
              if (!newVal) return;
              // Delayed so that the options have time to be rendered
              setTimeout(function () {
                elm.select2('val', controller.$viewValue);
                // Refresh angular to remove the superfluous option
                elm.trigger('change');
              });
            });
          }

          if (!isSelect) {
            // Set the view and model value and update the angular template manually for the ajax/multiple select2.
            elm.bind("change", function () {
              scope.$apply(function () {
                controller.$setViewValue(elm.select2('data'));
              });
            });

            if (opts.initSelection) {
              var initSelection = opts.initSelection;
              opts.initSelection = function (element, callback) {
                initSelection(element, function (value) {
                  controller.$setViewValue(value);
                  callback(value);
                });
              };
            }
          }
        }

        attrs.$observe('disabled', function (value) {
          elm.select2(value && 'disable' || 'enable');
        });

        scope.$watch(attrs.ngMultiple, function(newVal) {
          elm.select2(opts);
        });

        // Set initial value since Angular doesn't
        elm.val(scope.$eval(attrs.ngModel));
        console.log("INSIDE DIRECTIVE");
        console.log("scope.$eval(attrs.ngModel) = ")
        console.log(scope.$eval(attrs.ngModel));
        console.log("elm.val() = ");
        console.log(elm.val());

        // Initialize the plugin late so that the injected DOM does not disrupt the template compiler
        setTimeout(function () {
          elm.select2(opts);
        });
      };
    }
  };
}]);