Check if the output file are valid

[AkselsLedins]

Expected Behavior

Throw an error like this:

Current Behavior

The simulation runs smoothly

Possible Solution

Check simulation data before starting it.
Additionally, in:

func (v *Vehicle) Drive(allTrips []*Trip, step int, bonus int16) (score int) {
	// until the vehicle handles all scheduled rides
	if v.CurrentTrip >= len(v.Trips) {
		return
	}

	trip := allTrips[v.Trips[v.CurrentTrip]]
	trip.SomeoneIsOnIt()

We should check if someone is already on it