def rateable=(rateable)
      if opponent.nil?
        @rateable = false
        return
      end
      @rateable = case rateable
        when nil   then true   # default is true
        when false then false  # this is the only way to turn it off
        else true
      end
    end
def rateable=(rateable)
      if opponent.nil?
        @rateable = false
        return
      end
      @rateable = case rateable
        when nil   then true   # default is true
        when false then false  # this is the only way to turn it off
        else true
      end
    end
Rateable flag. If false, result is not rateable. Can only be true if there is an opponent.