Modeling Groups in Your DatabaseAdding a Groups TableThe Many-to-Many RelationshipOne-to-One, One-to-Many, Many-to-ManyJoins are Best Done with IDSUse a Join Table to Connect Users with GroupsTesting Group MembershipChecking for Group Membershipauthorize.php Needs a FunctionTake in a List of GroupsIterating Over Each GroupAllow, Deny, RedirectGroup-Specific MenusEntering Browser SessionsSessions Are Server-SideSessions Must Be StartedFrom $_COOKIE to $_SESSIONSessions Must Be Restarted, Too$_REQUEST Doesn’t Include $_SESSIONMenu, Anyone?And Then, Sign Out…Memory Lane: Remember That Phishing Problem?Why Would You Ever Use Cookies?