API POST error: MongoDB & Ionic App

What I'm Trying to do: Connect my mongolab db to my ionic app. (I'd use Firebase but Firebase doesn't have text search, which I need).

I followed the example at (https://scotch.io/tutorials/creating-a-single-page-todo-app-with-node-and-angular) for some guidance.

However, I'm getting the error:

Failed to load resource: the server responded with a status of 404 (Not Found) http://localhost:8100/api/todos

Structure of my files: -Project

+-www
+---js
------app.js
------server.js
------cordova.js
+-----controllers
+---css
+---img
+---lib
+---templates

I know that I'm probably missing something fundamental. I don't understand how my server.js is even loaded by ionic?

Here's a snippet (just the relevant parts) of my server.js

// set up ========================
var express  = require('express');
var app      = express();                               // create our app w/ express
var mongoose = require('mongoose');                     // mongoose for mongodb
var morgan = require('morgan');             // log requests to the console (express4)
var bodyParser = require('body-parser');    // pull information from HTML POST (express4)
var methodOverride = require('method-override'); // simulate DELETE and PUT (express4)
var uriUtil = require('mongodb-uri');

// configuration =================

var mongodbUri = 'mongodb://<myusername>:<mypass>@ds036648.mongolab.com:36648/<mydb>';
var mongooseUri = uriUtil.formatMongoose(mongodbUri);
mongoose.connect(mongooseUri);     // connect to mongoDB database on modulus.io

// listen (start app with node server.js) ======================================
app.listen(8100);
console.log("App listening on port 8100");

// define model =================
var Todo = mongoose.model('Todo', {
    text : String
});

// create todo and send back all todos after creation
app.post('/api/todos', function(req, res) {

    // create a todo, information comes from AJAX request from Angular
    Todo.create({
        text : req.body.text,
        done : false
    }, function(err, todo) {
        if (err)
            res.send(err);

        // get and return all the todos after you create another
        Todo.find(function(err, todos) {
            if (err)
                res.send(err)
            res.json(todos);
        });
    });

});

the html i'm using:

<!-- FORM TO CREATE TODOS -->
        <div id="todo-form" class="row">
            <div class="col-sm-8 col-sm-offset-2 text-center">
                <form>
                    <div class="form-group">

                        <!-- BIND THIS VALUE TO formData.text IN ANGULAR -->
                        <input type="text" class="form-control input-lg text-center" placeholder="I want to buy a puppy that will love me forever" ng-model="formData.text">
                    </div>

                    <!-- createToDo() WILL CREATE NEW TODOS -->
                    <button type="submit" class="btn btn-primary btn-lg" ng-click="createTodo()">Add</button>
                </form>
            </div>
        </div>

my controller:

angular.module('starter')
.controller('todosController', function($scope,$http) {

    $scope.formData = {};
    // when submitting the add form, send the text to the node API
    $scope.createTodo = function() {
        $http.post('/api/todos', $scope.formData)
            .success(function(data) {
                $scope.formData = {}; // clear the form so our user is ready to enter another
                $scope.todos = data;
                console.log(data);
            })
            .error(function(data) {
                console.log('Error: ' + data);
            });
    };