CHANGELOG.md in slack-ruby-client-0.12.0 vs CHANGELOG.md in slack-ruby-client-0.13.0

@@ -1,4 +1,11 @@
+### 0.13.0 (Next)
+
+* [#219](https://github.com/slack-ruby/slack-ruby-client/pull/219): Added support for `async-websocket` - [@dblock](https://github.com/dblock), [@ioquatix](https://github.com/ioquatix).
+* [#224](https://github.com/slack-ruby/slack-ruby-client/pull/224): Celluloid async support now uses  a thread per client - [@dblock](https://github.com/dblock).
+* [#224](https://github.com/slack-ruby/slack-ruby-client/pull/224): Attempt to shutdown EventMachine if a reactor wasn't already running on start - [@dblock](https://github.com/dblock).
+* Your contribution here.
+
 ### 0.12.0 (8/20/2018)
 
 * [#216](https://github.com/slack-ruby/slack-ruby-client/pull/216): Handle `Errno::ECONNRESET` and empty buffer reads with celluloid-io - [@dblock](https://github.com/dblock).
 * [#215](https://github.com/slack-ruby/slack-ruby-client/pull/215): Web API `groups_list`, `files_info`, `mpim_list`, `reactions_list` and `stars_list` now support cursor pagination - [@hotwatermorning](https://github.com/hotwatermorning).
 * [#215](https://github.com/slack-ruby/slack-ruby-client/pull/215): Added `apps_permissions_users_list` and `apps_permissions_users_request` - [@hotwatermorning](https://github.com/hotwatermorning).