|- src
|-- PcMagas
|---- Dropbox.php
|---- DropBoxFactory.php
|- web
|-- index.php

"autoload": {
        "psr-4":{
            "": "src/"
        }
    }

namespace PCMagas;

use GuzzleHttpClient;
use PCMagasExceptionsFileNotFoundException;

class DropboxFactory
{
    public static function fomeFunc()
    {
       //Do stuff
    }
}

require_once __DIR__ . '/../vendor/autoload.php';
use PCMagasDropboxFactory;
DropboxFactory::fomeFunc();

composer dump-autoload -o
cd ^project_root^
php -S localhost:8990

vagrant ssh

cd ~/code
composer dump-autoload -o