AngularJS failed to instantiate module -

im new in angularjs , im trying create authentication service i'm getting error.

error: [$injector:modulerr] failed instantiate module flujodecaja due to: [$injector:modulerr] failed instantiate module auth due to: [$injector:nomod] module 'auth' not available! either misspelled module name or forgot load it. if registering module ensure specify dependencies second argument. 

here code:

service.js

'use strict';  var mod = angular.module('auth',['restangular']);  mod.service('authservice', ['', function(){      var userisauthenticated = false;      this.setuserauthenticated = function(value){         userisauthenticated = value;     };      this.getuserauthenticated = function(){         return userisauthenticated;     });  }]); 

app.js

var angularmodule = angular.module('flujodecaja', [   'ngcookies',   'ngresource',   'ngsanitize',   'ngroute',   'restangular',   'auth' ]); 

index.html

<script src="bower_components/angular/angular.js"></script> <script src="bower_components/restangular/dist/restangular.js"></script> <script src="scripts/services/services.js"></script> <script src="scripts/app.js"></script> 

what i'm doing wrong?

thank in advance :)

corrected bit believe wrong.

mod.service('authservice', [function(){      var userisauthenticated = false;      this.setuserauthenticated = function(value){         userisauthenticated = value;     };      this.getuserauthenticated = function(){         return userisauthenticated;     };  }]);