Include internal gearman server in docs

Change-Id: I668206d7a07f665309ca392a8e5f1702c278c47e
diff --git a/etc/zuul.conf-sample b/etc/zuul.conf-sample
index 47e1d7e..edf1044 100644
--- a/etc/zuul.conf-sample
+++ b/etc/zuul.conf-sample
@@ -1,7 +1,8 @@
-[jenkins]
-server=https://jenkins.example.com
-user=jenkins
-apikey=1234567890abcdef1234567890abcdef
+[gearman]
+server=127.0.0.1
+
+[gearman_server]
+start=true
 
 [gerrit]
 server=review.example.com