Sesssion ID = 67sq0o6gue1ojh6q8uhdpq7ae4
Session name - PHPSESSID
Ustawiamy zmienna sesyjna 'USER'

Tablica $_COOKIE
=================
$_COOKIE[thema] = 0
$_COOKIE[PHPSESSID] = 67sq0o6gue1ojh6q8uhdpq7ae4

Tablica $_SESSION
==================
$_SESSION[user] = Kowalski