DateTimeField *** received a naive datetime (***) while time zone support is active

django报错：

/usr/local/lib/python2.7/dist-packages/Django-1.8.2-py2.7.egg/django/db/models/fields/__init__.py:1474: RuntimeWarning: DateTimeField Org.updatedAt received a naive datetime (2017-06-16 04:51:17) while time zone support is active.

RuntimeWarning)

参考：
http://www.zhixing123.cn/php/django-datetimefield-received-a-naive-da.html
时区问题，datetime.now()生成的不带时区的utc时间称为native time
使用django.utils.timezone.now()输出的是带时区的utc时间，称为active time
懒得一个个改，so：
# from datetime import datetime # 注释的
from django.utils import timezone as datetime # 添加的