If you start Squid as root, it will change its effective/real
	UID/GID to the user specified below.  The default is to change
	to UID to nobody.  If you define cache_effective_user, but not
	cache_effective_group, Squid sets the GID to the effective
	user's default group ID (taken from the password file) and
	supplementary group list from the from groups membership of
	cache_effective_user.