Add 2.9, 2.10 and 2.11 release summaries on release index

Change-Id: Ib3b4265e590c955fdd124a08e4dab3c8063807b4
diff --git a/pages/site/releases/README.md b/pages/site/releases/README.md
index d61b8a4..63385b1 100644
--- a/pages/site/releases/README.md
+++ b/pages/site/releases/README.md
@@ -100,7 +100,32 @@
 
 [Release notes for Gerrit 2.12](/2.12.html).
 
+## 2.11
+
+* [Issue 505](https://bugs.chromium.org/p/gerrit/issues/detail?id=505):
+Changes can be created and edited directly in the browser.
+
+* Many improvements in the new change screen.
+
+* The old change screen is removed.
+
+[Release notes for Gerrit 2.11](/2.11.html).
+
+## 2.10
+
+* Support for externally loaded plugins.
+
+* Customizable `My` menu.
+
+[Release notes for Gerrit 2.10](/2.10.html).
+
+## 2.9
+
+* The new change screen is now the default change screen.
+
+[Release notes for Gerrit 2.9](/2.9.html).
+
 ## Older Releases
 
-Release notes for releases prior to 2.12 can be found on the old
+Release notes for releases prior to 2.9 can be found on the old
 [documentation site](http://gerrit-documentation.storage.googleapis.com/ReleaseNotes/index.html).