code: function nextTurn(game, player) {
      if (player.has_turn === false) {  // we assume that player has the turn
          return;
      }
      player.has_turn = false;
  
      // give next player the turn
      var _players = Object.keys(game.players);
      var next_idx = (_players.indexOf(player.name) + 1) %
          _players.length;
      var next = game.players[_players[next_idx]];
      next.has_turn = true;
      // next player draws new pieces
      next.pieces = next.pieces.concat(game.drawPieces(
          6 - next.pieces.length));
  }
docs: Pass the turn to the next player,
  @param game: {obj} game object
  @param player: {obj} player object