def as_couch_json
      _attributes.inject({}) {|h, (k,v)| h[k] = v.respond_to?(:as_couch_json) ? v.as_couch_json : v; h}
    end
def as_couch_json
      _attributes.inject({}) {|h, (k,v)| h[k] = v.respond_to?(:as_couch_json) ? v.as_couch_json : v; h}
    end
Provide JSON data hash that can be stored in the database.
 Will go through each attribute value and request the `as_couch_json` method
 on each if available, or return the value as-is.