@jvanbaarsen I think better to follow for code style guide:
``` ruby
has_one :last_event, -> { order(events: { created_at: :desc }) }, class_name: 'Event', foreign_key: :project_id
```

`order(field: :type)` better then `order field: :type` or `order 'field TYPE'`
`foreign_key: :project_id` better then `foreign_key: "project_id"`
`class_name: Event` (`class_name: 'Event'.freeze` ugly) better then `class_name: 'Event'`

@randx that do you think?