Multiple parameters to crud

Hi, I'm having, probably a basic issue for some, problems with my edit crud.

I have this two routes in my web.php.

// Categories
Route::resource('docs', 'CategoryController');

// Articles
Route::resource('docs/{category}/', 'ArticleController');

The categories rout generates the url docs/category_name, by having it I can create categories in separate table.

The second route is for creating articles. I'd like to display it like docs/category_name/article_name.

But then I get the error "Missing required parameters for [Route: store] [URI: docs/{category}]"

This is my edit crud:

public function create($category)
{
    return view('articles.create')
    ->with('category', $category);
}

Still does it not work.

In my articles.edit file I have the following:

{!! Form::open(['route' => 'store']) !!}

I can't find where I'm wrong. Please provide me with some valuable information. Thank you!