Merge pull request #184 from json-schema-org/slack

Added link to Slack

Author: Relequestual

_includes/footer.html

@@ -12,7 +12,7 @@ <h2 class="footer-heading">{{ site.title | escape }}</h2>
             {% include icon-github.html username=site.github_username %}
           </li>
           {% endif %}
-          <li>Discussion: <a href="https://groups.google.com/forum/#!forum/json-schema">Google Groups</a></li>
+          <li>Discussion:<a href="https://join.slack.com/t/json-schema/shared_invite/enQtMjk1NDcyNDI2NTAwLTcyYmYwMjdmMmUxNzZjYzIxNGU2YjdkNzdlOGZiNjIwNDI2M2Y3NmRkYjA4YmMwODMwYjgyOTFlNWZjZjAyNjg">Slack</a> - <a href="https://groups.google.com/forum/#!forum/json-schema">Google Groups</a></li>
           <li>Site edits: <a href="https://github.com/json-schema-org/json-schema-org.github.io">GitHub repo for site</a></li>
         </ul>
       </div>

index.md

@@ -97,4 +97,4 @@ Questions? Feeling helpful? Get involved on:
 
 -   the [GitHub repo](http://github.com/json-schema-org/json-schema-spec)
 -   the [Google Group](https://groups.google.com/forum/#!forum/json-schema)
--   the [IRC channel](irc://chat.freenode.net/json-schema) ([Freenode Webchat](https://webchat.freenode.net/?channels=json-schema))
+-   the [Slack channel](https://join.slack.com/t/json-schema/shared_invite/enQtMjk1NDcyNDI2NTAwLTcyYmYwMjdmMmUxNzZjYzIxNGU2YjdkNzdlOGZiNjIwNDI2M2Y3NmRkYjA4YmMwODMwYjgyOTFlNWZjZjAyNjg)