improvement(PlaceByNationalId): update README.md

.gitignore

@@ -12,4 +12,5 @@ build/
 # Directory created by dartdoc
 doc/api/
 
-.idea/
+.idea
+/.idea/

README.md

@@ -22,7 +22,7 @@
 - [x] [Converting Persian numbers to Arabic / English numbers and reverse](#converting-persian-numbers-to-arabic--english-numbers-and-reverse---source)
 - [x] [Checking a string has/is Persian](#checking-a-string-hasis-persian---source)
 - [x] [Validating Iranians national id](#validate-iranian-national-id---source)
-- [ ] Finding city and province names by national id
+- [x] [Finding city and province names by national id](#find-city-and-province-name-by-national-code---source)
 - [x] [Calculating bills](#calculating-bill---source)
 - [x] [Checking IBAN of the bank account (_SHEBA_)](#checking-iban-of-the-bank-account-sheba---source)
 - [x] [Validating ATM card number](#validating-atm-card-number---source)
@@ -71,10 +71,24 @@ verifyIranianNationalId(nationalID); // true
 nationalID = '00000';
 verifyIranianNationalId(nationalID); // false
 
+/// verify nationalId with extension methods over [String] class
 nationalID = '';
 nationalID.isIranianNationalId; // false
 ```
 
+- #### Find city and province name by national code - [source](https://github.com/persian-tools/dart-persian-tools/blob/master/lib/src/core\get_place_by_national_id\get_place_by_national_id.dart)
+
+```dart
+final place = getPlaceByIranNationalId('0084575948');
+place?.city.name; // تهران مرکزی
+place?.province.name; // تهران
+
+/// get place with extension methods over [String] class
+final nationalId = '2110990147';
+nationalId.getPlaceNationalId?.city.name; // گرگان
+nationalId.getPlaceNationalId?.province.name; // گلستان
+```
+
 - #### Calculating Bill - [source](https://github.com/persian-tools/dart-persian-tools/blob/master/lib/src/core/bill/bill.dart)
 
 ```dart