Add Slack workspace

Author: oezden

contact-us.md

@@ -0,0 +1,11 @@
+---
+layout: default
+title: Contact us
+nav_order: 9
+---
+
+# Contact us
+
+The easiest way to contact us is via our Slack workspace. Please use the invitation link below to join our Slack workspace.
+
+[ElastiSim Slack](https://join.slack.com/t/elastisim/shared_invite/zt-23ln6g4dc-DZwf0b1TV~qgjVkPKQGI4A){: .btn }