Release notes for Gerrit 2.9.1

Change-Id: Ic5ed2f40af8f544e9f340695e8ce06e91ec08cd9
diff --git a/ReleaseNotes/index.txt b/ReleaseNotes/index.txt
index 2588d5b..8e7cac6 100644
--- a/ReleaseNotes/index.txt
+++ b/ReleaseNotes/index.txt
@@ -5,6 +5,7 @@
 Version 2.9.x
 -------------
 * link:ReleaseNotes-2.9.html[2.9]
+* link:ReleaseNotes-2.9.1.html[2.9.1]
 
 [[2_8]]
 Version 2.8.x