Add codereview.settings file.

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/1654143002 .

codereview.settings

diff --git a/codereview.settings b/codereview.settings
new file mode 100644
index 0000000..daf2596
--- /dev/null
+++ b/codereview.settings
@@ -0,0 +1,3 @@
+CODE_REVIEW_SERVER: codereview.chromium.org
+CC_LIST: mojo-reviews@chromium.org
+PROJECT: mojo_base