Add link to Arabic translation

Author: marijnh

html/index.html

@@ -137,6 +137,7 @@ <h3>Third Edition</h3>
   <h3>Second Edition</h3>
 
   <ul class=translations>
+    <li><a href="https://rabahboudia.gitbooks.io/arabic-eloquent-js/content/index.html">عَرَبِيّ‎ (Arabic)</a></li>
     <li><a href="https://to6esko.github.io/">Български (Bulgarian)</a></li>
     <li><a href="https://braziljs.github.io/eloquente-javascript/">Português (Portuguese)</a></li>
     <li><a href="https://karmazzin.gitbooks.io/eloquentjavascript_ru/content/">Русский (Russian)</a></li>