public function registerEmployee(Request $request)
 {
     $username = $request->input('username');
     $password = $request->input('password');
     $firstname = $request->input('firstname');
     $lastname = $request->input('lastname');
     $tel = $request->input('tel');
     $email = $request->input('email');
     $role = $request->input('role');
     $specialty = $request->input('specialty');
     // $valid = $request->input('valid');
     // username not repeat
     // fill all request
     $error = [];
     if (!$username) {
         $error[] = 'username_not_found';
     } else {
         if (User::where('username', $username)->first()) {
             $error[] = 'username_exist';
         }
     }
     if ($password == null) {
         $error[] = 'password_not_found';
     }
     if ($firstname == null) {
         $error[] = 'firstname_not_found';
     }
     if ($lastname == null) {
         $error[] = 'lastname_not_found';
     }
     if ($tel == null) {
         $error[] = 'tel_not_found';
     }
     if ($email == null) {
         $error[] = 'email_not_found';
     }
     if ($role == null) {
         $error[] = 'role_not_found';
     }
     if ($role == 'Doctor' && $specialty == null) {
         $error[] = 'specialty_not_found';
     }
     if (sizeof($error) != 0) {
         return response()->json(["success" => false, "message" => $error]);
     }
     $prototype = ['username' => $username, 'password' => $password, 'firstname' => $firstname, 'lastname' => $lastname, 'tel' => $tel, 'email' => $email, 'role' => $role];
     if ($role == 'Doctor') {
         $prototype['specialty'] = $specialty;
     }
     $employee = HospitalEmployee::create($prototype);
     return response()->json(["success" => true, "data" => $employee->toArray()]);
 }