Meetting serializable error when store record to Redis after insert.

[bahuafeng]

raceback (most recent call last):
File "ssp2db.py", line 41, in
ad.save()
File "/home/work/.jumbo/lib/python2.7/site-packages/thing/thing.py", line 348, in save
self._after_insert()
File "/home/work/.jumbo/lib/python2.7/site-packages/thing/thing.py", line 271, in _after_insert
json.dumps(self.to_dict()))
File "/home/work/.jumbo/lib/python2.7/json/init.py", line 231, in dumps
return _default_encoder.encode(obj)
File "/home/work/.jumbo/lib/python2.7/json/encoder.py", line 201, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/home/work/.jumbo/lib/python2.7/json/encoder.py", line 264, in iterencode
return _iterencode(o, 0)
File "/home/work/.jumbo/lib/python2.7/json/encoder.py", line 178, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: datetime.datetime(2016, 9, 21, 19, 51, 33) is not JSON serializable

[bahuafeng]

When storing record to Redis，msgpack maybe better than json.dumps.
Hope to be helpful. :)