Is this there a better way to use AngularJS to create a simple login?

Question

I'm brand new to AngularJS. I would like advice as to whether I'm approaching the design of a simple login section of an app built with Angular correctly.

The app consists of two view partials: login.html and user-admin.html. Of what I have so far, the user types their username into the login page. A controller checks if that username is listed in users.json file, if so then login is successful and the user-admin.html partial replaces login.html.

I feel that the controller which checks the typed username against the usernames in users.json could be written better. Is there a more efficient way than using the 'for' statement?

To develop this further I will want to add some way of preventing a logged in user seeing the login page and a non-logged in user seeing the admin page. My initial thought is to use cookies. But would the 'Angular' way be to create a service that perpetuates the logged in status between views? If that is the best way to implement it, what would that service look like?

app.js

angular.module('userApp', ["ngResource"]).

config(['$routeProvider', function($routeProvider) {
    $routeProvider.
        when('/login', {templateUrl: 'partials/login.html',   controller: LoginCtrl}).
        when('/loggedin', {templateUrl: 'partials/user-admin.html', controller: UserCtrl}).
        otherwise({redirectTo: '/login'});
}],[ '$locationProvider', function($locationProvider) {
    $locationProvider.html5Mode = true;
}]).

factory("User", function($resource) {
    return $resource("users/:userId.json", {}, {
        query: {method: "GET", params: {userId: "users"}, isArray: true}
    });
});

controllers.js

function LoginCtrl($scope, $route, $routeParams, $location, User) {
    $scope.users = User.query();
    $scope.loginUser = function() {
        var loggedin = false;
        var totalUsers = $scope.users.length;
        var usernameTyped = $scope.userUsername;

        for( i=0; i < totalUsers; i++ ) {
            if( $scope.users[i].name === usernameTyped ) {
                loggedin = true;
                break;
            }
        }

        if( loggedin === true ) {
            alert("login successful");
            $location.path("/loggedin");
        } else {
            alert("username does not exist")
        }
    }
}

function UserCtrl($scope, $route, $routeParams, $location) {
    $scope.logoutUser = function() {
        $location.path("/login");
    }
}

users.json

[
    {
        "userId": 1,
        "name": "Tommy",
        "password": "123456",
        "log": {
            "registration": "2012.12.14",
            "lastLog": "2013.01.15"
        }
    },
    {
        "userId": 2,
        "name": "Anne",
        "password": "123456",
        "log": {
            "registration": "2012.12.24",
            "lastLog": "2012.12.29"
        }

    },
    {
        "userId": 3,
        "name": "Miles",
        "password": "abc",
        "log": {
            "registration": "2013.02.01",
            "lastLog": "2013.02.01"
        }
    }
]

login.html

<h1>Login</h1>
<section>
    <form ng-submit="loginUser();">
        <label for"userUsername">Username</label><input type="text" id="userUsername" ng-model="userUsername">
        <input type="submit" value="Login">
    </form>
</section>