Update contributor document
We now prefer to use Guava (previously known as Google Collections).
Change-Id: I81187422173a9edba486dc305e72c7e579c5347f
diff --git a/Documentation/dev-contributing.txt b/Documentation/dev-contributing.txt
index 2609b05..2ede544 100644
--- a/Documentation/dev-contributing.txt
+++ b/Documentation/dev-contributing.txt
@@ -191,6 +191,7 @@
on slow links. If the action buttons are disabled, they cannot
be resubmitted and the user can see that Gerrit is still busy.
* GWT EventBus is the new way forward.
+ * ...and so is Guava (previously known as Google Collections).
Tests
