报错如下：
sqlalchemy.exc.InternalError
sqlalchemy.exc.InternalError: (cymysql.err.InternalError) (1054, “Unknown column ‘user.create_time’ in ‘field list’”) [SQL: ‘SELECT user.password AS user_password, user.create_time AS user_create_time, user.status AS user_status, user.id AS user_id, user.nickname AS user_nickname, user.phone_number AS user_phone_number, user.email AS user_email, user.confirmed AS user_confirmed, user.beans AS user_beans, user.send_counter AS user_send_counter, user.receive_counter AS user_receive_counter, user.wx_open_id AS user_wx_open_id, user.wx_name AS user_wx_name
FROM user
WHERE user.id = %s’] [parameters: (1,)] (Background on this error at: http://sqlalche.me/e/2j85)

代码如下：

class Base(db.Model):
    __abstract__ = True
    create_time = Column('create_time', Integer)
    status = Column(SmallInteger, default=1)

    def __init__(self):
        self.create_time = int(datetime.now().timestamp())

使用create_time前没问题，使用__init__构造方法为create_time赋值后报错。
从git上clone下来的项目coding-194有同样问题，登录报错，请问老师这是什么问题？