Add Hack Dayton image

docs/index.html

@@ -321,7 +321,7 @@ <h2 class="anchored" data-anchor-id="our-family-of-user-groups">Our family of us
 <td>3rd Thursdays <span class="citation" data-cites="6pm">@6pm</span></td>
 </tr>
 <tr class="even">
-  <td><img src="img/groups/gem_city_ml_social.png" class="img-fluid"></td>
+  <td><img src="img/groups/HackDayton.jpg" class="img-fluid"></td>
   <td><strong>Hack Dayton</strong> A monthly hacker meet-up focus on sharing knowledge and hands experiences around the offensive cybersecurity industry in the Dayton area.</td>
   <td>Brett Ewing</td>
   <td>The last Friday <span class="citation" data-cites="6pm">@6pm</span></td>