/**
  * Update the avatar url.
  *
  * @param  \Illuminate\Http\Request  $request
  * @param  int  $id
  * @return void
  */
 public function changeAvatar(Request $request, $id)
 {
     $baseDir = 'avatar';
     $this->validate($request, ['photo' => 'required|mimes:jpg,jpeg,png,bmp']);
     $file = $request->file('photo');
     $name = $file->getClientOriginalName();
     $file->move($baseDir, $name);
     $user = User::find($id);
     $user->avatar = '/' . $baseDir . '/' . $name;
     $user->save();
 }