Error running qinfo

[dcollinsn]

Seems like the difference "stopped - started" is being treated as a DateTime, and something is looking for a time zone on it...

Python 3.6, Django 2.1.2, django-q 1.0.1, django-redis 4.10.0. Pytz 2018.7, not that I think it matters.

System check identified some issues:

WARNINGS:
?: (django_mysql.W003) The character set is not utf8mb4 for database connection 'default'
	HINT: The default 'utf8' character set does not include support for all Unicode characters. It's strongly recommended you move to use 'utf8mb4'. See: https://django-mysql.readthedocs.io/en/latest/checks.html#django-mysql-w003-utf8mb4
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.6/dist-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.6/dist-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.6/dist-packages/django/core/management/base.py", line 316, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.6/dist-packages/django/core/management/base.py", line 353, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.6/dist-packages/django_q/management/commands/qinfo.py", line 41, in handle
    info()
  File "/usr/local/lib/python3.6/dist-packages/django_q/monitor.py", line 127, in info
    exec_time = last_tasks.aggregate(time_taken=Sum(F('stopped') - F('started')))
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/query.py", line 370, in aggregate
    return query.get_aggregation(self.db, kwargs)
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/sql/query.py", line 488, in get_aggregation
    result = next(compiler.apply_converters((result,), converters))
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/sql/compiler.py", line 1009, in apply_converters
    value = converter(value, expression, connection)
  File "/usr/local/lib/python3.6/dist-packages/django/db/backends/mysql/operations.py", line 252, in convert_datetimefield_value
    value = timezone.make_aware(value, self.connection.timezone)
  File "/usr/local/lib/python3.6/dist-packages/django/utils/timezone.py", line 264, in make_aware
    return timezone.localize(value, is_dst=is_dst)
  File "/usr/local/lib/python3.6/dist-packages/pytz/__init__.py", line 223, in localize
    if dt.tzinfo is not None:
AttributeError: 'decimal.Decimal' object has no attribute 'tzinfo'

[madEng84]

Duplicate (but with more important issue info) of #245 issue

It seems to be a problem only of mysql vendor.