CONTRIBUTORS: Andrea Spadaccini (Google CLA)

R=golang-dev, rsc
CC=golang-dev, spadaccio
https://golang.org/cl/5460046

CONTRIBUTORS

@@ -41,6 +41,7 @@ Alexander Orlov <alexander.orlov@loxal.net>
 Alexander Reece <awreece@gmail.com>
 Alexey Borzenkov <snaury@gmail.com>
 Amrut Joshi <amrut.joshi@gmail.com>
+Andrea Spadaccini <spadaccio@google.com>
 Andrei Vieru <euvieru@gmail.com>
 Andrew Balholm <andybalholm@gmail.com>
 Andrew Gerrand <adg@golang.org>