Explaining the idea of Is it possible for Backpack\CRUD\app\Http\Controllers\CrudController on method setup to change the underlying query? eg. /admin/vocabulary/{vid}/overview Overview CRUD of terms that are children of vocabulary {vid}?

VocabularyCrudController.php

<?php

namespace App\Http\Controllers\Admin;

use Backpack\CRUD\app\Http\Controllers\CrudController;
use App\Http\Requests\VocabularyCrudRequest as StoreRequest;
use App\Http\Requests\VocabularyCrudRequest as UpdateRequest;

class VocabularyCrudController extends CrudController {

    public function setup() {

        $this->crud->setModel('App\Vocabulary');
        $this->crud->setRoute('admin/vocabulary');
        $this->crud->setEntityNameStrings('vocabulary', 'vocabularies');
        $this->crud->setColumns(['name']);
        $this->crud->addField([
            'name' => 'name',
            'label' => 'Vocabulary',
            'type' => 'text',
            'placeholder' => 'Your title here',
        ]);
        $this->crud->addField([
            'name' => 'description',
            'label' => 'Description',
            'type' => 'ckeditor',
            'placeholder' => 'Your textarea text here',
        ]);
        $this->crud->addButtonFromView('line', 'listofterms', 'listofterms', 'beginning');
    }

    public function store(StoreRequest $request)
    {
        return parent::storeCrud();
    }

    public function update(UpdateRequest $request)
    {
        return parent::updateCrud();
    }
}