sample_schema

{
    "_id": ObjectId,
    "user": ObjectId,
    "goal": Number,
    "semester": String,
    "publisher": String,
    "location": String,
    "gender": String,
    "is_VIP": Boolean,
    "VIP_type": String,
    "payments": [{"date": Date, "type": String, "period": [Date, Date]}],
    "registTime": Date,
    "daily": [String],  # 所有活跃过的日期
    "weekly": {
        "201601": {
            "videos": {
                "54cc7835abc5bbb971f99be0": ["A", 2, 1]  # 视频类型, 观看次数, 完成次数
            },
            "problems": {
                "54c708798bac81fccbd4bbd5": ["step", 3, 1]  # 题目类型, 做题次数, 做对次数
            },
            "login": [0, 2, 3, 0, 1, 5, 3],  # 本周每天登录次数
            "learning_time": {"video": Number, "problem": Number},  # 本周学习时间
            "is_VIP": Boolean,  # 本周是否是VIP
        }
    },
    "cycles": {
        "201601": String,   # 每周所处生命周期
        "201602": String
    }
}