'integer', ]; public function event(): BelongsTo { return $this->belongsTo(Event::class); } public function driver(): BelongsTo { return $this->belongsTo(User::class, 'user_id'); } public function passengers(): HasMany { return $this->hasMany(EventCarpoolPassenger::class, 'carpool_id'); } public function remainingSeats(): int { return $this->seats - $this->passengers->count(); } }