Mention github contributors in thanks.html

src/gui/about.ui

@@ -369,7 +369,11 @@
         <number>6</number>
        </property>
        <item>
-        <widget class="QTextBrowser" name="te_thanks"/>
+        <widget class="QTextBrowser" name="te_thanks">
+         <property name="openExternalLinks">
+          <bool>true</bool>
+         </property>
+        </widget>
        </item>
       </layout>
      </widget>

src/gui/thanks.html

@@ -10,5 +10,6 @@
     <p>I also want to thank Στέφανος Αντάρης (santaris@csd.auth.gr) and Mirco Chinelli (infinity89@fastwebmail.it) for working on Mac OS X packaging.</p>
     <p>I am grateful to Peter Koeleman (peter@qbittorrent.org) and Mohammad Dib (mdib@qbittorrent.org) for working on qBittorrent port to Windows.</p>
     <p>Thanks a lot to our graphist Mateusz Toboła (tobejodok@qbittorrent.org) for his great work.</p>
+    <p>Thanks to all contributors on <a href="https://github.com/qbittorrent/qBittorrent/graphs/contributors">GitHub</a>.</p>
 </body>
 </html>