How can I fix this node.js path issue?

I'm in the process of refactoring my server.js file and trying to incorporate MVC pattern. I'm running into a problem trying to access my controller from my routes.js. I've tried just about every variation of absolute and relative path that I can think but I must be missing something. Here is my directory structure: enter image description here

And from my routes.js, here is my code:

module.exports = function ( app, passport, auth ) {
    var Clients = require('controllers/clients');
    app.get('/clients', Clients.list);
}

I don't think this is relevant, but here is my clients controller:

var mongoose = require('mongoose')
    , Client  = mongoose.model('Client');

exports.list = function( req, res ) {
    Client.find( function( err, clients ) {
        res.renderPjax('clients/list', { clients: clients, user: req.user });
    });
}

Here is the error that I'm getting when trying to access my controller from routes:

module.js:340
    throw err;
          ^
Error: Cannot find module 'controllers/clients'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at module.exports (/Users/sm/Desktop/express3-mongoose-rememberme/app/routes.js:5:16)
    at Object.<anonymous> (/Users/sm/Desktop/express3-mongoose-rememberme/server.js:334:24)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)

I'm sure it's something simple that I'm over looking. How can I access my controller from my routes?

To require something that isn't a separate package (isn't in node_modules), you need to use an explicitly relative path:

require('./controllers/clients')

For more information, see the documentation.

Local Modules

require(...) takes a relative path for local modules

require('./controllers/clients')

Installaed modules

For modules installed via npm install -S foo, use the syntax

require('foo')