Call to a member function associate() on a non-object - laravel

Question

Error Message: http://puu.sh/d4l0F/5b0ac07e68.png
I've even saved the $transportation object before trying to create associations. I've verified that both $transporation, $from and $to are all their respective objects and they are.
I'm sure I'm missing something stupid here but I'm out of ideas.
My code:
class RideBuilder implements RideBuilderInterface
{
public function create(Advance $advance)
{
$ride = new Ride;
if($ride->validate(Input::all())) {
$ride->save();
$to = Location::find(Input::get('dropoffLocation'));
$from = Location::find(Input::get('pickupLocation'));
$transportation = new Transportation;
$transportation->save();
$transportation->transportable()->associate($ride);
$transportation->to()->associate($to);
$transportation->from()->associate($from);
$event = new Event;
$event->start = Input::get('ridePickUpTime');
$event->save();
$event->eventable->save($transportation);
$event->subjectable->save($advance);
}
return $ride;
}
}
Location Model:
class Location extends Elegant
{
protected $table = 'locations';
public $rules = array(
'label' => 'required|min:2',
'street' => 'required',
'city' => 'required',
'state' => 'required',
'type' => 'required',
);
public function advance()
{
return $this->belongsTo('Booksmart\Booking\Advance\Model\Advance');
}
public function locationable()
{
return $this->morphTo();
}
}
Transportation Model:
class Transportation extends Elegant
{
protected $table = 'transportations';
public function event()
{
$this->morphOne('Booksmart\Component\Event\Model\Event');
}
public function start_location()
{
$this->belongsTo('Booksmart\Component\Location\Model\Location', 'start_location');
}
public function end_location()
{
$this->belongsTo('Booksmart\Component\Location\Model\Location', 'end_location');
}
}

Answer 1

I had a similar issue. I made the stupid mistake of not adding the "return" in the relationship method!
Make sure you return the relationship... Obviously this will not work:
public function medicineType()
{
$this->belongsTo('MedicineType', 'id');
}
This is the correct way:
public function medicineType()
{
return $this->belongsTo('MedicineType', 'id');
}
Easy to miss, hard to debug...