garmin_activity_id uniqueness becomes per-user (UNIQUE(user_id, garmin_activity_id), added in Task 1) so two users' Garmin accounts can never collide even in the unlikely event their activity ids coincide.
garmin_activity_id uniqueness becomes per-user (UNIQUE(user_id, garmin_activity_id), added in Task 1) so two users' Garmin accounts can never collide even in the unlikely event their activity ids coincide.