Add St. Petersburg, FL chapter logo

Author: julianduque

hexdex.html

@@ -155,6 +155,9 @@ <h1 data-i18n="hexdex-h1">Hexdex</h1>
           <a class="imglink" href="https://github.com/nodeschool/amsterdam/" title="Amsterdam">
             <img class="hex" src="/images/nodeschool-amsterdam.svg" alt="Amsterdam Hexagon">
           </a>
+          <a class="imglink" href="https://github.com/nodeschool/st-petersburg/" title="St. Petersburg, FL">
+            <img class="hex" src="/images/nodeschool-stpete.png" alt="St. Petersburg, FL Hexagon">
+          </a>
           <img class="hex" src="/images/nodeschool-blank.png" alt="blank hexagon" aria-hidden="true">
       </div>
     </div>