Going from 2->3... Problem accessing model

Kind of modelling my latest project after Vokuro and running into an issue. When I try to do User::findFirst([...]), I'm getting a 500 error that " Class 'Zipline\Controllers\User' not found in /var/www/html/zipline/app/controllers/NoauthajaxController.php on line 11"

Here is part of my config:

    'application' => [
        'controllersDir' => APP_PATH . '/controllers/',
        'modelsDir' => APP_PATH . '/models/',
        //'formsDir' => APP_PATH . '/forms/',
        'viewsDir' => APP_PATH . '/views/',
        'libraryDir' => APP_PATH . '/library/',
        //'pluginsDir' => APP_PATH . '/plugins/',
        //'cacheDir' => BASE_PATH . '/cache/',
    ],

Here is my loader:

    <?php

    use Phalcon\Loader;

    $loader = new Loader();

    /**
     * We're a registering a set of directories taken from the configuration file
     */
    $loader->registerNamespaces([
        'Zipline\Models' => $config->application->modelsDir,
        'Zipline\Controllers' => $config->application->controllersDir,
        //'Zipline\Forms' => $config->application->formsDir,
        'Zipline' => $config->application->libraryDir
    ]);

    $loader->register();

    // Use composer autoloader to load vendor classes
    require_once BASE_PATH . '/vendor/autoload.php';

Here is my controller:

    <?php namespace Zipline\Controllers;

    use Phalcon\Http\Response;
    use Phalcon\Http\Request;

    class NoauthajaxController extends ControllerBase {

        public function userloginAction() {
            $response = $this->getResponse();
            $request = $this->getRequest();
            $U = User::findFirst([
                'conditions' => 'email = :username:',
                'bind' => [
                    'username' => $request->username
                ]
            ]);
            if (empty($U)) {
                $response['error'] = "Invalid username or password.";
            } else if ($U->login($request)) {
                $response['success'] = true;
                $response['data']['user'] = $this->session->get('auth_user');
            } else {
                $response['error'] = $this->errors($U->getMessages());
            }

            $this->respond($response);
        }
    }

Here is my model:

    <?php namespace Zipline\Models;

    use Phalcon\Mvc\Model;
    use Phalcon\Mvc\Model\Message;
    /*
    use Phalcon\Validation;
    use Phalcon\Mvc\Model\Validator\Uniqueness;
    use Phalcon\Mvc\Model\Validator\Email;
    use Phalcon\Mvc\Model\Validator\PresenceOf;
    use Phalcon\Mvc\Model\Behavior\SoftDelete;
    */

    class User extends Model {

        public function initialize() {
            $this->setSource("users");
        }

        public function login() {
            var_dump($this->toArray());
        }

    }

Trying to make this as simple as possible, but for some reason when I call User::findFirst, it's thinking I'm looking for a controller named User... Not the model.