map-reduce map

map = function(){
	var quarter;
	var mins = this.time.getMinutes();
	if(mins <= 14)
		quarter = 0;
	else if(mins<=29)
		quarter = 15;
	else if(mins<=44)
		quarter = 30;
	else
		quarter = 45;
    var time_at_minute = new Date(this.time.getFullYear(),
        this.time.getMonth(),
        this.time.getDate(),
        this.time.getHours(),
        quarter);

	emit(time_at_minute, { 
		count: 1,
		price: this.price, 
		volume: this.amount, 
		total: this.total,
		low: this.price,
		high: this.price,
		open: this.price,
		close: this.price,
	});
}