I made the type String not Hash, because it is stored in the DB as a string, and CC json-decodes it only when sending it to GW (https://github.com/cloudfoundry/cloud_controller_ng/pull/56/files#L1R161).

we could make the default here be "{}" instead of nil.   But for compatibility with clients that do not send BO, we need to enforce this default at L1R161.  So it seemed simpler to me to just write this default-value code once.