Adding NodeSchool Dhaka Hexagon image to hexdex page

Author: ishtiaque23

hexdex.html

@@ -161,6 +161,9 @@ <h1 data-i18n="hexdex-h1">Hexdex</h1>
           <a class="imglink" href="https://github.com/nodeschool/reykjavik/" title="Reykjavik">
             <img class="hex" src="/images/nodeschool-rvk.svg" alt="Reykjavik Hexagon">
           </a>
+          <a class="imglink" href="https://github.com/nodeschool/dhaka" title="Dhaka">
+            <img class="hex" src="/images/nodeschool-dhaka.png" alt="Dhaka Hexagon">
+          </a>
           <img class="hex" src="/images/nodeschool-blank.png" alt="blank hexagon" aria-hidden="true">
       </div>
     </div>