public function postProfile(Request $request)
 {
     $userName = $request->input('name');
     $userEmail = $request->input('email');
     $userRealName = $request->input('realname');
     $userSchool = $request->input('userSchoolName');
     $userGrade = $request->input('userGrade');
     $userOrder = $request->input('userOrder');
     $userRole = $request->input('role');
     $userDescription = $request->input('userDescription');
     $currentUser = Auth::user();
     //update user info
     $currentUser->description = $userDescription;
     $currentUser->name = $userName;
     $currentUser->realname = $userRealName;
     $currentUser->email = $userEmail;
     $currentUser->role = $userRole;
     $section = Section::getSectionByGradeAndOrder($userGrade, $userOrder, $userSchool);
     //        find the matching section with grade and order.
     if (!$section) {
         //            means don't exist this section, please create a new Section.
         $newSection = new Section();
         $newSection->grade = $userGrade;
         $newSection->order = $userOrder;
         $newSection->schools_id = $userSchool;
         //            setting the number of the section
         $newSection->total += 1;
         $newSection->save();
     } else {
         //            add the 1 to total number of the exist section
         $section->total += 1;
     }
     //        先去teachingSection table中查找到用户的对应信息
     if ($userTeachingSection = TeachingSection::where()) {
         $currentUser->save();
     }
     //        the first method.
     /*        session()->flash('flash_message', '你的个人信息修改成功');
             session()->flash('flash_message_important', true);*/
     /*        return redirect('/dashboard')->with([
                 'flash_message' => '你的个人信息修改成功',
                 'flash_message_important' => true
             ]);*/
     //        \Flash::success()
     //        flash->success('你的个人信息修改成功');
     //        Flash::success('你的个人信息修改成功');
     //        flash()->success('你的个人信息修改成功');
     flash()->overlay('你的个人信息修改成功', '成功');
     return redirect('/dashboard');
 }