表一:
[
{list: [{city_id: 0001, key1: value1},{city_id: 0002, key2: value2}...]}
]

表二（city表）:
[
{_id: 0001, scene: ['天安门','故宫','王府井']},
{_id: 0002, scene: ['东方明珠','外滩']}
.....
]

如上描述：表1里有个list字段是个数组对象， 想要的结果是：通过list数组下面的的每个city_id查询city表，把scene字段添加到表一对应的数组中

结果为：
[
{list: [{city_id: 0001, key1: value1, scene: ['天安门','故宫','王府井']},{city_id: 0002, key2: value2, scene: ['东方明珠','外滩']}...]}
]