Add link to Russian translation

Author: marijnh

html/index.html

@@ -106,6 +106,7 @@ <h2>Translations</h2>
   <ul class=translations>
     <li><a href="http://to6esko.github.io/">Български (Bulgarian)</a></li>
     <li><a href="https://github.com/braziljs/eloquente-javascript">Português (Portuguese)</a></li>
+    <li><a href="https://karmazzin.gitbooks.io/eloquentjavascript_ru/content/">Русские (Russian)</a></li>
   </ul>
 
 </article>