Add hcmc-vietnam hexagon

Ho Chi Minh City - Vietnam Hexagon

Author: okaiji

hexdex.html

@@ -110,6 +110,9 @@ <h1 data-i18n="hexdex-h1">Hexdex</h1>
           <a class="imglink" href="https://github.com/nodeschool/toronto" title="Toronto">
             <img class="hex" src="/images/nodeschool-toronto.svg" alt="Toronto Hexagon">
           </a>
+          <a class="imglink" href="https://github.com/nodeschool/hcmc-vietnam" title="Ho Chi Minh City - Vietnam">
++            <img class="hex" src="images/nodeschool-hcmc-vietnam.svg" alt="Ho Chi Minh City - Vietnam Hexagon">
++          </a>
           <img class="hex" src="/images/nodeschool-blank.png" alt="blank hexagon" aria-hidden="true">
       </div>
     </div>