def uri(append_rev = false)
      return nil if new?
      couch_uri = "#{database.root}/#{CGI.escape(id)}"
      if append_rev == true
        couch_uri << "?rev=#{rev}"
      elsif append_rev.kind_of?(Integer)
        couch_uri << "?rev=#{append_rev}"
      end
      couch_uri
    end
def uri(append_rev = false)
      return nil if new?
      couch_uri = "#{database.root}/#{CGI.escape(id)}"
      if append_rev == true
        couch_uri << "?rev=#{rev}"
      elsif append_rev.kind_of?(Integer)
        couch_uri << "?rev=#{append_rev}"
      end
      couch_uri
    end
Returns the CouchDB uri for the document