add possibility to show already done shifts in admin active view

includes/pages/admin_active.php

@@ -1,4 +1,5 @@
 <?php
+
 function admin_active_title() {
   return _("Active angels");
 }
@@ -12,8 +13,12 @@ function admin_active() {
   $count = $forced_count;
   $limit = "";
   $set_active = "";
+  
   if (isset($_REQUEST['search']))
     $search = strip_request_item('search');
+  
+  $show_all_shifts = isset($_REQUEST['show_all_shifts']);
+  
   if (isset($_REQUEST['set_active'])) {
     $ok = true;
     
@@ -98,6 +103,7 @@ function admin_active() {
       FROM `User` LEFT JOIN `ShiftEntry` ON `User`.`UID` = `ShiftEntry`.`UID` 
       LEFT JOIN `Shifts` ON `ShiftEntry`.`SID` = `Shifts`.`SID` 
       WHERE `User`.`Gekommen` = 1
+      " . ($show_all_shifts ? "" : "AND `Shifts`.`end` < " . time()) . "
       GROUP BY `User`.`UID` 
       ORDER BY `force_active` DESC, `shift_length` DESC" . $limit);
   
@@ -154,6 +160,7 @@ function admin_active() {
   return page_with_title(admin_active_title(), array(
       form(array(
           form_text('search', _("Search angel:"), $search),
+          form_checkbox('show_all_shifts', _("Show all shifts"), $show_all_shifts),
           form_submit('submit', _("Search")) 
       )),
       $set_active == "" ? form(array(