Add hexdex for Haarlem

Author: J.P. Wesselink

hexdex.html

@@ -143,6 +143,9 @@ <h1 data-i18n="hexdex-h1">Hexdex</h1>
           <a class="imglink" href="https://github.com/nodeschool/nyc/" title="New York City, NY">
             <img class="hex" src="/images/nodeschool-nyc.svg" alt="New York City Hexagon">
           </a>
+          <a class="imglink" href="https://github.com/nodeschool/haarlem/" title="New York City, NY">
+            <img class="hex" src="/images/nodeschool-haarlem.svg" alt="Haarlem Hexagon">
+          </a>
           <img class="hex" src="/images/nodeschool-blank.png" alt="blank hexagon" aria-hidden="true">
       </div>
     </div>