Laravel 5, can't insert via request method doesn't exist - laravel-5

Question

That's what i'm trying to do without any success:
In welcome.blade I have a foreach with some boards and subboards(random generated by user) where you can click on subboard and go something like this /subboardOne. I got this on my routes.php
Route::get('/{subboaName}', 'ThreadController#index');
Route::post('/{subboaName}', 'ThreadController#store');
then you can post a thread on this subboard via form but since i really don't know how laravel knows where he is, the form is something like this:
<form class="form col-md-12 center-block" role="form" method="POST" action="/{{$subboardcoll->id}}">
this $subboardcoll->id comes from the controller, where it sends via the index function the collection:
public function index($subboard)
{
$subboardcoll = Subboard::where('subboaName', $subboard)->first();
$threads = Thread::where('subboaId', $subboardcoll->id)
->orderBy('created_at', 'desc')
->get();
return view('threads.thread', compact('threads', 'subboardcoll'));
}
then i'm trying to send my form and store the thread autoinserting the subboardId but laravel doesn't recognize subboards method:
public function store(Request $request)
{
$this->validate($request, [
'comentario' => 'required|max:2000',
//'g-recaptcha-response' => 'required|recaptcha',
//'imagen' => 'required',
]);
$request->subboards()->threads()->create([
'thrName' => $request->nombre,
'thrComment' => $request->comentario,
'thrImg' => $request->imagen,
'thrSubject' => $request->tema,
]);
return redirect()->back();
}
And gives me this erorr:
BadMethodCallException in Macroable.php line 81: Method subboards does not exist.
Can you guys helpme to know why? also is there better form to do what i'm trying? im newbie on laravel, thanks
EDIT:
Thread.php
public function subboard()
{
return $this->belongsTo(Subboard::class, 'subboaId');
}
Subboard.php
public function thread()
{
return $this->hasMany(Thread::class);
}

Answer 1

The method subboards do not exist in a request object. Consider doing this
public function store($id, Request $request)
{
$this->validate($request, [
'comentario' => 'required|max:2000',
//'g-recaptcha-response' => 'required|recaptcha',
//'imagen' => 'required',
]);
Subboard::find($id)->threads()->create([
'thrName' => $request->nombre,
'thrComment' => $request->comentario,
'thrImg' => $request->imagen,
'thrSubject' => $request->tema,
]);
//Alternative query statement
Subboard::where('id', $id)->first()->threads()->create([.....
return redirect()->back();
}