def putcat (k, v)

      k = k.to_s; v = v.to_s

      @db.putcat(k, v)
    end
def putcat (k, v)

      k = k.to_s; v = v.to_s

      @db.putcat(k, v)
    end
Appends the given string at the end of the current string value for key k.
 If there is no record for key k, a new record will be created.

 Returns true if successful.