add codereview config to the repo

R=rsc
CC=golang-dev
http://codereview.appspot.com/2012049
diff --git a/lib/codereview/codereview.cfg b/lib/codereview/codereview.cfg
new file mode 100644
index 0000000..93b55c0
--- /dev/null
+++ b/lib/codereview/codereview.cfg
@@ -0,0 +1 @@
+defaultcc: golang-dev@googlegroups.com