AngularJS $resource service's $save() POSTs to incorrect route - angularjs

Question

I have a basic factory returning a $resource called User:
angular.module('appServices').factory('User', [
'$resource',
function($resource){
return $resource('http://localhost:3000/users/:username', {username:'#username'});
}]);
In my UserController.js file I try to do something fairly simple:
angular.module("myApp").controller('UserController', ['$scope', '$routeParams', 'User',
function($scope, $routeParams, User){
var user = new User({email:'user#example.com', username: 'johndoe', password: 'mySecurePassw0rd!'});
user.$save();
}]);
I expect the $save() function to make a POST request to /users, however in the console I get http://localhost:3000/users/johndoe 404 response, because the route is obviously not set up on the server for POST requests with the username parameter appended...
Why is it that it does so in my code sample ? From the examples I have seen on the internet, the $save() function does not take into account the username and should directly POST to /users in my case.
Any help would be appreciated!
EDIT
I think I got the error (as always, immediately after posting the question on SO...)
It is probably because of the default parameter {username: "#username"} I specified in the $resource, as it expects there to be a username parameter by default ?
So the correct way to do it would be to return this resource from the factory:
return $resource('http://localhost:3000/users/:username');
correct ?

Answer 1

Username is a natural primary key. Unless you use switch to a surrogate one (generated on server side), you will need two different methods for entity creating and updating:
var User = $resource(
'/users/:username',
{
username: '#username'
},
{
save: {
methods: 'POST',
url: '/users'
},
update: {
method: 'PUT'
}
}
);