Add ways to discuss LC

Author: Chris Erdmann

_extras/discuss.md

@@ -3,4 +3,12 @@ layout: page
 title: "Discussion"
 root: ..
 ---
-FIXME: general discussion and further reading for learners.
+
+There are many ways to discuss Library Carpentry lessons:
+
+- Join our [Gitter discussion forum](https://gitter.im/LibraryCarpentry/).
+- Join our [Slack organisation](https://swc-slack-invite.herokuapp.com/) and #libraries channel.
+- Stay in touch with our [Topicbox Group](https://carpentries.topicbox.com/groups/discuss-library-carpentry).
+- Follow updates on [Twitter](https://twitter.com/LibCarpentry).
+- Make a suggestion or correct an error by [raising an Issue](https://github.com/LibraryCarpentry/lc-open-refine/issues).
+