code: def vote(direction = :up)
        assert_current_song
        api('room.vote',
          :roomid => room.id,
          :section => room.section,
          :val => direction,
          :songid => id,
          :vh => digest("#{room.id}#{direction}#{id}"),
          :th => digest(rand),
          :ph => digest(rand)
        )
        true
      end
docs: Vote for the song.
  
   @param [Symbol] direction The direction to vote the song (:up or :down)
   @return [true]
   @raise [Turntabler::Error] if the command fails
   @raise [Turntabler::Error] if the song is not playing in the current song
   @example
     song.vote         # => true
     song.vote(:down)  # => true