/**
  * Display the specified resource.
  *
  * @param  int  $section_id - default to the first section
  * @return Response
  */
 public function show($section_id = null)
 {
     if (!$section_id) {
         $section = \Nexus\Section::with('sections', 'topics')->first();
     } else {
         $section = \Nexus\Section::with('sections', 'topics')->where('id', $section_id)->first();
     }
     \Nexus\Helpers\ActivityHelper::updateActivity(\Auth::user()->id, "Browsing <em>{$section->title}</em>", action('Nexus\\SectionController@show', ['id' => $section->id]));
     $breadcrumbs = \Nexus\Helpers\BreadcrumbHelper::breadcrumbForSection($section);
     return view('sections.index', compact('section', 'breadcrumbs'));
 }