Add COPYING file with Apache 2.0 license

The original bucklets source, such as it is, was forked from the
Gerrit Code Review project, which is Apache licensed. All
contributions since then have been through, which requires contributors
to have signed the Android Open Source Project CLA. Thus we can
default the code in this repo to Apache.

Change-Id: If49b567c17b8e14cff92ef64bf2c0f769c453b9d
1 file changed