Moving top-level namespace files into app/ folder - http://slashnode.com/definitive-laravel-4-to-laravel-5-migration-guide/

User.php

<?php namespace Acme\Models;

/**
 * In Laravel 4.2: app/src/Models/User.php
 * 
 * In Laravel 5.x: app/Models/User.php
 */
 
class User
{
    /** class code here */
}