[Web] Add git head info

data/web/debug.php

@@ -4,6 +4,7 @@ require_once "inc/prerequisites.inc.php";
 if (isset($_SESSION['mailcow_cc_role']) && $_SESSION['mailcow_cc_role'] == "admin") {
 require_once "inc/header.inc.php";
 $_SESSION['return_to'] = $_SERVER['REQUEST_URI'];
+$git_last = array_pop(file('/git_head'));
 
 ?>
 <div class="container">
@@ -42,6 +43,21 @@ $_SESSION['return_to'] = $_SERVER['REQUEST_URI'];
           $vmail_df = explode(',', json_decode(docker('dovecot-mailcow', 'post', 'exec', $exec_fields), true));
         ?>
         <div role="tabpanel" class="tab-pane active" id="tab-containers">
+          <div class="panel panel-default">
+            <div class="panel-heading">
+              <h3 class="panel-title">Version information</h3>
+            </div>
+            <div class="panel-body">
+              <div class="row">
+                <div class="col-sm-3">
+                  <p>Git head</p>
+                </div>
+                <div class="col-sm-9">
+                  <a target="_blank" href="https://github.com/mailcow/mailcow-dockerized/commit/<?=explode(' ', $git_last)[1];?>"><?=explode(' ', $git_last)[1];?></a>
+                </div>
+              </div>
+            </div>
+          </div>
           <div class="panel panel-default">
             <div class="panel-heading">
               <h3 class="panel-title">Disk usage</h3>