/**
  * Update the specified resource in storage.
  *
  * @param  Request  $request
  * @param  int  $id
  * @return Response
  */
 public function update(Request $request, $id)
 {
     $row = \App\Difficulty::find($id);
     $row->update($request->all());
     return redirect()->route('difficulty.index');
 }