Laravel related model data population for multiple checkboxes

gistfile1.php

<?php

class Product extends Eloquent {

	public function categories()
	{
		return $this->belongsToMany('Category');
	}

}

<?php

class Category extends Eloquent {

	public function products() 
	{
		return $this->belongsToMany('Product');
	}

}

// Product edit

/**
 * Show the form for editing the specified resource.
 *
 * @param  int  $id
 * @return Response
 */
public function edit($id)
{
	$product = $this->product->find($id);
	if (is_null($product))
	{
		return Redirect::route('products.index');
	}
	$this->data['product'] = $product;
	$this->data['categories'] = Category::all();
	$selectedCategories = $product->categories()->get()->toArray();
	$selectedCategories = array_pluck($selectedCategories, 'id');
	$this->data['selectedCategories'] = $selectedCategories;
	return View::make('products.edit', $this->data);
}

// form

<legend>Categories</legend>
@foreach($categories as $category)
<div class="checkbox">
  <label>
    @if(in_array($category->id, $selectedCategories))
    {{ Form::checkbox('categories[]', $category->id, true) }}
    @else
    {{ Form::checkbox('categories[]', $category->id, false) }}
    @endif
    {{ $category->name }}
  </label>
</div>
@endforeach