What's the rationale behind EventRelation model?

[khvn26]

Just asking to clarify how justified is a separate model for defining relations.

Why not use a ForeignKey or subclass it to define a custom field?

[llazzaro]

The class EventRelation allows you to relate the event model with any object. If we add a ForeignKey to the event you need to add a specific column for each app or model. Of course you can subclass and define a custom field, but the EventRelation allows you to do it without migrations.