commented on some other stuff

adminarea.php

@@ -8,9 +8,10 @@
 <script src="ressources/js/bootstrap.min.js"></script>
 <?php
 session_start();
-if($_SESSION['isadmin'] == 0) {
+//just a page to list all admin functions:
+if($_SESSION['isadmin'] == 0) { //but first a check if you've got admin rights. if not, destroy the session and go back to start.
     die ('No rights for you! <meta http-equiv="refresh" content="0; URL=logout.php">');
-}
+} //this is purely a cosmetic effect. no harm could be done from here. it's merely a html page with a little check if you've got the right rights.
 echo '<div class="alert alert-danger" role="alert">heres the admin world</div>';
 
 echo '<a href="adminarea_useradmin.php"><button class="btn btn-primary">User Admin</button></a>';