Express server status 404 error with AngularJS $http.post

So I have setup separate ports for my express server and my angular front end , using yeoman and grunt for the first time. This is also my first time attempting a web project with this client/server structure and I have hit a wall.

I have a signup form in my front end under localhost:9000/signup and when I click submit I get the following back

{firstname: "test", lastname: "test", email: "test", password1: "test", password2: "test"}
angular.js:12759 POST http://localhost:9000/signup 404 (Not Found)

(anonymous) @ angular.js:12759
sendReq @ angular.js:12492
serverRequest @ angular.js:12244
processQueue @ angular.js:17051
(anonymous) @ angular.js:17095
$digest @ angular.js:18233
$apply @ angular.js:18531
(anonymous) @ angular.js:27346
dispatch @ jquery.js:5206
elemData.handle @ jquery.js:5014
angular.js:14700 Possibly unhandled rejection: {"data":"Cannot POST     /signup\n","status":404,"config":
{"method":"POST","transformRequest":        
[null],"transformResponse:[null],"jsonpCallbackParam":"callback","url":"/signup","data":
{"firstname":"test","lastname":"test","email":"test","password1":"test",
"password2":"test"},"headers":{"Accept":"application/json, text/plain, */*","Content-Type":"application/json;charset=utf-8"}}
,"statusText":"Not Found","xhrStatus":"complete"}

The first line is me printing the results of the form back to the browsers console. Second is 404 on /signup and I am not sure if that is the express route or the client /signup?

Here is my signup.js that is located in /routes folder in express

// Include Express
var express = require('express');
// Initialize the Router
var router = express.Router();

// Setup the Route
router.post('/', function (req, res) {

// show the request body in the command line
console.log(req.body);

// return a json response to angular
res.json({
    'msg': 'success!'
});
});

// Expose the module
module.exports = router;

And I have included it in my app.js file in express with

var signup = require('./routes/signup');
...
app.use('/signup', signup);

Abd finally my signup.js folder which is the controller for the /signup form.

'use strict';

angular.module('clientApp') // make sure this is set to whatever it is in your client/scripts/app.js
  .controller('SignupCtrl', function ($scope, $http) { // note the added $http depedency

    // Here we're creating some local references
    // so that we don't have to type $scope every
    // damn time
    var user,
        signup;

    // Here we're creating a scope for our Signup page.
    // This will hold our data and methods for this page.
    $scope.signup = signup = {};

    // In our signup.html, we'll be using the ng-model
    // attribute to populate this object.
    signup.user = user = {};

    // This is our method that will post to our server.
    signup.submit = function () {

      // make sure all fields are filled out...
      // aren't you glad you're not typing out
      // $scope.signup.user.firstname everytime now??
      if (
        !user.firstname ||
        !user.lastname ||
        !user.email ||
        !user.password1 ||
        !user.password2
      ) {
        alert('Please fill out all form fields.');
        return false;
      }

      // make sure the passwords match match
      if (user.password1 !== user.password2) {
        alert('Your passwords must match.');
        return false;
      }

      // Just so we can confirm that the bindings are working
      console.log(user);


    $http.post('/signup', user)
    .then(function(response) {
      console.log(response.data);
  });
}
  });

I am officially stumped and would love some insight - any help is much appreciated.