13 GEO是什么？还可以定义新的数据类型吗？
用户在叫车的时候，叫车应用会根据用户的经纬度位置（例如经度 116.054579，纬度 39.030452），查找用户的附近车辆，并进行匹配
GEOADD cars:locations 116.034579 39.030452 33
GEOADD cars:locations 116.134579 39.030452 34
GEOADD cars:locations 116.234579 39.030452 35
GEOADD cars:locations 116.334579 39.030452 36
GEOADD cars:locations 116.434579 39.030452 37
GEOADD cars:locations 116.534579 39.030452 38
GEOADD cars:locations 116.634579 39.030452 39
GEOADD cars:locations 116.734579 39.030452 40
GEOADD cars:locations 116.834579 39.030452 41
GEOADD cars:locations 116.934579 39.030452 42
GEOADD cars:locations 116.234579 39.030452 43
GEOADD cars:locations 116.034579 39.030452 39
GEORADIUS cars:locations 116.054579 39.030452 5 km ASC COUNT 10
