Add codereview.settings page for using rietveld

codereview.settings

diff --git a/codereview.settings b/codereview.settings
new file mode 100644
index 0000000..2c8718b
--- /dev/null
+++ b/codereview.settings
@@ -0,0 +1,3 @@
+# This file is used by gcl to get repository specific information.
+CODE_REVIEW_SERVER: codereview.chromium.org
+VIEW_VC: https://chromium.googlesource.com/external/mojo/+/