Error: [ng:areq] Argument 'AppCtrl' is not a function, got undefined

I am building an ionic app and i keep getting this error and dont know why.

This is my code

app.js 

var app = angular.module('loanstreet', ['ionic', 'ui.select', 'ion-autocomplete', 'loanstreet.controllers', 'ngCordova', 'loanstreet.services', 'ngMockE2E', 'loanstreet.constants', 'frapontillo.ex.filters'])
.config(function($stateProvider, $urlRouterProvider, $httpProvider) {
  $stateProvider

  .state('login', {
    url: "/login",
    templateUrl: "templates/login.html",
    controller: 'AppCtrl'
  })
});

js/controllers/controllers.js

var app = angular.module('loanstreet.controllers', []);

js/controllers/app_controller.js

angular.module('loanstreet.controllers')
.controller('AppCtrl', function($scope, $ionicModal, $timeout, $state, AuthenticationService, $location, $rootScope) {
})

index.html 

 <script src="js/app.js"></script>
 <script src="js/controllers/controllers.js"></script>
 <script src="js/controllers/app_controller.js"></script>
<body ng-app="loanstreet">

    <ion-nav-view></ion-nav-view> 
  </body>

I am a bit confused as to why it doesnt recognize the AppCtrl even though i have already defined it in the code. I read it has to do with angular 1.3x but still cant figure it out.

Any help appreciated

You're trying to define new modules with

angular.module('loanstreet.controllers').controller

But without a second argument, angular.module gets (doesn't create) a module.

Try:

angular.module('loanstreet.controllers',[]).controller