add link to request adding an event

Author: StevenClontz

events/index.md

@@ -5,4 +5,7 @@ title: Events
 
 Times displayed are in Eastern Time - New York.
 
+Want to add your event to this calendar?
+[Make your request in our Zulip chat!](https://code4math.zulipchat.com/#narrow/stream/441393-Events/topic/code4math.20calendar)
+
 <iframe src="https://calendar.google.com/calendar/embed?src=5a4f9e3c51ca2e99cb3d0fc725919d3f4cc83de3a41a808f352ba7e25439a2ac%40group.calendar.google.com&ctz=America%2FNew_York&mode=AGENDA&showNav=1" style="border: 0" width="100%" height="600" frameborder="0" scrolling="no"></iframe>