Symfony: Fatal Error: Class not found in app/console

I'm trying to get commands from command line to work using symfony. I have the following folder structure:

• app console
• src
  • Source
    • Commands twitterCommand.php

Now in my console file I have the following code:

#!/usr/bin/env php
<?php

require_once '/../vendor/autoload.php';

use Source\Commands\TwitterCommand;
use Symfony\Component\Console\Application;
use Endroid\Twitter\Twitter;

//API Keys
...

$client = new Twitter($consumerKey, $consumerSecret, $accessToken,   $accessTokenSecret);

$application = new Application();
$application->add(new TwitterCommand($client));
$application->run();

And then in my TwitterCommand.php i have the following:

<?php 

namespace Source\Commands;

use Twitter;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Formatter\OutputFormatterStyle;

class TwitterCommand extends Command
{
private $client;

public function __construct(Twitter $client)
{
    parent::__construct();
    $this->client = $client;
}

protected function configure()
{
    $this
        ->setName('freq:tweet')
        ->setDescription('Show the tweets')
}

protected function execute(InputInterface $input, OutputInterface $output)
{

    // Retrieve the user's timeline
    $tweets = $twitter->getTimeline(array(
        'count' => 5
    ));

    // Or retrieve the timeline using the generic query method
    $response = $twitter->query('statuses/user_timeline', 'GET', 'json', $parameters);
    $tweets = json_decode($response->getContent());

    $output->writeln($tweets);
}
}

The problem is I'm getting a 'Fatal error: Class 'Source\Commands\TwitterCommand' not found in C:...' and the error is sent in this line:

$application->add(new TwitterCommand($client));

Any idea on what am I doing wrong?