cmd/admin: add instructions for setting up Cloud SQL
cmd/admin: add instructions for setting up Cloud SQL

Reading test passes. :-)

Change-Id: I34e0c34da84cbb4ee51900857c8f7224af1f34e4
Reviewed-on: https://upspin-review.googlesource.com/2780
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@google.com>
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@google.com>

upspin/upspin,upspin/upspin