Add botmakers slack to my start page

www/start.html

@@ -15,6 +15,7 @@
 
 <button data-url="https://zefr.slack.com/" class="app btn btn-primary">ZEFR Slack</button>
 <button data-url="https://la-engineers.slack.com/" class="app btn btn-primary">LA-Engineers Slack</button>
+<button data-url="https://botmakers.slack.com/" class="app btn btn-primary">Botmakers Slack</button>
 <button data-url="https://www.facebook.com/" class="app btn btn-primary">Facebook</button>
 
 {% endblock %}