Remove the ability to register to the Summit

Change-Id: Ieea9bb0944adfbf7d94de95606dcae07b268bb50

navbar.md

diff --git a/navbar.md b/navbar.md
index 3402f72..2dda4f9 100644
--- a/navbar.md
+++ b/navbar.md
@@ -4,7 +4,6 @@
 * [Speakers](/speakers.md)
 * [Overview](/overview.md)
 * [Conduct Policy](/conduct-policy.md)
-* **[Register](https://gus2018.eventbrite.com)**
 
 [home]: /index.md
 [logo]: images/gerritusersummit2018.png