Added Slack hours.

Author: kgodey

content/community/contents.lr

@@ -10,6 +10,8 @@ CC has an active Slack community open to the public. [Sign up here](http://slack
 * `#cc-gsoc` – for Google Summer of Code related discussion
 * `#cc-usability` – for soliciting feedback on new releases from the community
 
+CC's tech team are all in the Americas and someone is usually around on Slack between 11:00 and 23:00 UTC.
+
 #### Mailing List
 
 Join the [current CC Developers mailing list here](https://groups.google.com/a/creativecommons.org/forum/#!forum/cc-developers).