The problem is incorrect usage of ng-app. Only declare ng-app once for your application, usually on the html element.
Then declare other modules as dependencies of your main module.
I put the ng-app declaration on the html tag and put your ng-routing in the app module, getting rid of the views module.
http://plnkr.co/edit/btL2QMyHxhDLH7cxZ1YV
var app = angular.module('app', ['ngRoute']);
app.config(function($routeProvider, $locationProvider){
$routeProvider.
when('/developers', {templateUrl: 'dev.html', controller: 'DevCtrl'}).
when('/designers',{templateUrl: 'design.html',controller: 'DesignCtrl'}).
otherwise({ redirectTo: '/index' });
// $locationProvider.html5Mode(true);
});
<html ng-app="app">
You can also put the view-logic in a separate module, but usually you will then also put it in a different file.
The html5mode is disabled because it triggered an error (it’s a little bit tricky to make that work).
Note: it actually is possible to use multiple ng-app by manually bootstrapping them, but you really shouldn’t do this unless you have a very good reason for it.