Story short, I need to save in the history the changes made on a Many-To-Many fields of one of my models.
I can see from: https://github.com/Kyruus/django-simple-his
This is an old open question, and might be irrelevant by now, but from looking into the code of the project in question, it seems like the last line on the ClassRoom model should be changed to
history = HistoricalRecords(m2m_fields=['students'])