added credits

static/templates/frontpage.st

@@ -33,6 +33,13 @@
             That's it.
             </p>
         </fieldset>
+        <fieldset>
+            <legend>Credits</legend>
+            I`m very grateful to the people who supported me writing and testing this software:
+            <ul>
+                <li>Erik Heinzf for sharing his knowledge on email protocols and pitfalls</li>
+            </ul>
+        </fieldset>
         «footer()»
     </body>
 </html>