gistfile1.js

// TestController.js

module.exports = function (app) {

	return function($scope) {
		$scope.somevar = 'Whatever';
	};

};

// App.js

var angular = require('angular');
var uiRouter = require('ui-router');

var app = angular.module('testApp', [uiRouter]);

app.config(function($stateProvider) {
	$stateProvider
    .state('home', {
      url: "/",
      controller: 'TestController',
      templateUrl: "templates/home.html"
    })
})
.controller('TestController', require('TestController')(app));


// This works, but ideally you want to do it like this. Which doesn't work as it can't match the name of the controller ..

// App.js

var angular = require('angular');
var uiRouter = require('ui-router');

var app = angular.module('testApp', [uiRouter]);

app.config(function($stateProvider) {
	$stateProvider
    .state('home', {
      url: "/",
      controller: require('TestController')(app),
      templateUrl: "templates/home.html"
    })
})