add buildbucket.config

Change-Id: Idb2f1917f3ce44dfc8e5fde1667e99fa3f1dc823

buildbucket.config

diff --git a/buildbucket.config b/buildbucket.config
new file mode 100644
index 0000000..c190a7e
--- /dev/null
+++ b/buildbucket.config
@@ -0,0 +1,5 @@
+[host]
+  git = "r8.googlesource.com"
+  gerrit = "r8-review.googlesource.com"
+
+[bucket "ci"]