go.empty: prototype for new subrepository

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5572056
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
new file mode 100644
index 0000000..1c4577e
--- /dev/null
+++ b/CONTRIBUTORS
@@ -0,0 +1,3 @@
+# This source code was written by the Go contributors.
+# The master list of contributors is in the main Go distribution,
+# visible at http://tip.golang.org/CONTRIBUTORS.