Blacklist: State in user profile if there's an unpayed payment

[britschki]

Idea:

• add list of user's courses to user profile with an associated payment status:

  • ok
  • first reminder
  • second reminder
  • teacher intervention
  • blacklisted

• add a global status field to user profile table with the following options:

  • ok
  • first reminder
  • second reminder
  • teacher intervention
  • blacklisted

• global status is worst case status across all open/closed payments

• create blacklist table

• celery task to update user status periodically (daily).

  • calculate payment status for each course
  • send corresponding e-mails if status has changed (recipients TBD).
  • recalculate global status
  • add users to blacklist if necessary.

• when user makes payment, update status accordingly

• also write unit tests

[renatobellotti]

A first version of the models is implemented (not committed yet). The blacklist status of the subscription is set to 'OK' if the subscription is payed. Still to do:

• Write celery task that updates the blacklist status for unpaid subscriptions (e. g. daily)
• Add code to send out emails if the blacklist status has been changed.

[renatobellotti]

Update (commit a488ef9b9d5cf410397da5a71fad05fd761cc77c):

The code to update the blacklist is implemented, but not tested yet (not even executed...). Remaining tasks:

• let Celery call the update_entire_blacklist() function in courses/services.py periodically
• write intervention email to teachers when this stage is reached
• make sure blacklisted people cannot enrol in courses and display a message for them

[renatobellotti]

Another thing to do is to use reversion to track changes in the blacklist state.