issue_105

#105
Problem:
datetime: datetime.datetime’s utcnow() and utcfromtimestamp() are deprecated and will be removed in a future version. Instead, use timezone-aware objects to represent datetimes in UTC: respectively, call now() and fromtimestamp() with the tz parameter set to datetime.UTC. (Contributed by Paul Ganssle in gh-103857.)
Solution:
To add new function to get actual datetime_now with timezone and remove timezone to save the datebase models unchanged (to use postgresql and sqlite).
Conclusion:
All timestamps converts to utc timezone and stores without timezone in the database

Reviewed-by: Aloento
Reviewed-by: Vladimir Hasko <[email protected]>
Reviewed-by: Ilia Bakhterev