微信好友昵称为emoji表情符号时，无法写入数据库。

[tiancegit]

sqlalchemy.exc.InternalError: (pymysql.err.InternalError) (1366, "Incorrect string value: '\xF0\x9F\x8C\xBF' for column 'nick_name' at row 1") [SQL: 'INSERT INTO users (create_at, id, sex, nick_name, signature, province, city) VALUES (%(create_at)s, %(id)s, %(sex)s, %(nick_name)s, %(signature)s, %(province)s, %(city)s)'] [parameters: {'signature': '做自己想做的事！！！……', 'city': '佛山', 'sex': 2, 'nick_name': '🌿',