Angular + RequireJS：无法读取undefined的属性'controller'

Question

好朋友，我在使用Angle with RequireJS时遇到问题。以下是方便的代码结构：

main.js

require.config({
    baseUrl: '/',
    shim: {
        angular: {
            exports: "angular"
        },
        route: {
            deps: ["angular"]
        },
        app:{
            deps:['route']
        },
        controller:{
            deps:['app']
        }
    },
    paths: {
        //Libery
        angular:            'assets/js/lib/angular',
        route:              'assets/js/lib/angular-route',
        //APP
        app:                'app/app',
        //Controller
        controller:         'app/controller/controller',
    },

    deps: ['controller']
});

app.js

define('app', ['angular', 'route'], function (angular, route) {
    var app = angular.module('app',['ngRoute']);

    app.config(function($routeProvider, $locationProvider)
    {
       $locationProvider.html5Mode(true);

       $routeProvider

       .when('/', {
          templateUrl : 'app/views/home.php',
          controller  : 'home',
       })

       .when('/sobre', {
          templateUrl : 'app/views/sobre.php',
          controller  : 'sobre',
       })

       .when('/contato', {
          templateUrl : 'app/views/contato.php',
          controller  : 'contato',
       })

       .otherwise ({ redirectTo: '/' });
    });    
});

controller.js

define('controller', ['app'], function (app) {

    app.controller('home', function($rootScope, $location){
       $rootScope.activetab = $location.path();
    });

    app.controller('sobre', function($rootScope, $location){
       $rootScope.activetab = $location.path();
    });

    app.controller('contato', function($rootScope, $location){
       $rootScope.activetab = $location.path();
    }); 

});

问题是无法读取未定义的属性'controller' 在RequireJS中，相信依赖是正确的！ 谢谢你。