Sesssion ID = uk9oregi4njmdg881i0bljqeo5
Session name - PHPSESSID
Ustawiamy zmienna sesyjna 'USER'

Tablica $_COOKIE
=================
$_COOKIE[thema] = 0
$_COOKIE[PHPSESSID] = uk9oregi4njmdg881i0bljqeo5

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