Periodic tasks can get queued with different default args/kargs

[jkemp101]

When tasktiger starts and automatically schedules periodic tasks the task ID is the hash of:
{"args": null, "func": "my_function", "kwargs": null}

If the same task is scheduled in a Python shell with my_function.delay() the hash is of:
{"args": [], "func": "my_function", "kwargs": {}}
which will be a different ID than the previous version. This can cause the same periodic task to be scheduled twice with two different IDs.

[] and {} are probably the more sane defaults. Two options to fix:

• Force the hash to be None for [] and {} in gen_unique_id
• Calculate the hash using [] and {} and have a migration to unschedule existing tasks that can be used before deploying the new version of TaskTiger so that two sets of periodic tasks don't end up scheduled.