Update README.md

Author: rdnasim

README.md

@@ -1,5 +1,6 @@
+
 <p align="center" >
-  <img src="https://www.bkash.com/sites/all/themes/bkash/logo.png?87980">
+  <img src="https://www.bkash.com/images/favicon.png">
 </p>
 
  <h1 align="center">bKash(BD) Mobile Finance Payment Gateway Flutter Package</h1>
@@ -18,61 +19,132 @@ This is a [Flutter package](https://pub.dartlang.org/packages/flutter_bkash) for
 
 Check the package in <a target="_blank" href="https://github.com/codeboxrcodehub/flutter-bkash" rel="noopener">github</a> and also available in <a href="https://pub.dartlang.org/packages/flutter_bkash" rel="noopener nofollow" target="_blank">flutter/dart package</a>
 ## How to use:
-
 Depend on it, Run this command With Flutter:
-
 ```
 $ flutter pub add flutter_bkash
 ```
-
 This will add a line like this to your package's `pubspec.yaml` (and run an implicit **`flutter pub get`**):
-
 ```
 dependencies:
-    flutter_bkash: ^1.0.0
+    flutter_bkash: ^0.1.3
+```
+Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more. Import it, Now in your Dart code, you can use:
 ```
-
-Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.
-Import it
-
-Now in your Dart code, you can use:
-
-`
 import 'package:flutter_bkash/flutter_bkash.dart';
-`
+```
+## Features
+- Pay using bKash without an agreement
+- Create a bKash agreement for future payments
+- Pay using bKash with an agreement
 
 ## Usage
-
 Official Link for API documentation and demo checkout
 - [bKash API Specifications](https://developer.bka.sh/v1.2.0-beta/reference)
 - [bKash Payment Checkout Demo](https://merchantdemo.sandbox.bka.sh/frontend/checkout)
 
-Examples for see the `/example` folder.
+### Initialize the `FlutterBkash` instance:
 
-**Here is the example code**
+***Sandbox***
 ```
 final flutterBkash = FlutterBkash();
+```
+***Production*** 
+```
+final flutterBkash = FlutterBkash(
+	credentials: BkashCredentials(
+    username: "app_username",
+    password: "app_password",
+    appKey: "app_key",
+    appSecret: "app_secret",
+    isSandbox: false,
+  ),
+);
+```
+> Make sure to replace the provided credentials with your own bKash sandbox or production credentials depending on your development environment.
+
+### Pay without Agreement
+To make a payment without an agreement, use the `pay` method:
+
+***Request***
+```
+final result = await flutterBkash.pay(
+      context: context, // BuildContext context
+      amount: 100.0, // amount as double
+      merchantInvoiceNumber: "invoice123",
+);
+```
+***Response***
+```
+BkashPaymentResponse(
+	trxId: AFI60BAC94, 
+	payerReference:  , 
+	paymentId: TR0011fd4uZMS1687062024354, 
+	customerMsisdn: 01877722345, 
+	merchantInvoiceNumber: tranId, 
+	_executeTime: 2023-06-18T10:22:31:623 GMT+0600
+)
+```
+### Create Agreement
+To create a new agreement, use the `createAgreement` method:
+
+***Request***
+```
+final result = await flutterBkash.createAgreement(context: context);
+```
+***Response***
+```
+BkashAgreementResponse(
+	payerReference:  , 
+	paymentId: TR0000RCHQGmX1687063332607, 
+	customerMsisdn: 01877722345, 
+	agreementId: TokenizedMerchant02P1AIJ7G1687063381235, 
+	_executeTime: 2023-06-18T10:43:01:235 GMT+0600
+)
+```
+### Pay with Agreement
+To make a payment with an existing agreement, use the `payWithAgreement` method:
 
+***Request***
+```
+final result = await flutterBkash.payWithAgreement(
+  context: context, // BuildContext context
+  amount: 100.0, // type as double
+  agreementId: "agreement123",
+  merchantInvoiceNumber: "invoice123",
+);
+```
+***Response***
+```
+BkashPaymentResponse(
+	trxId: AFI60BAC94, 
+	payerReference:  , 
+	paymentId: TR0011fd4uZMS1687062024354, 
+	customerMsisdn: 01877722345, 
+	merchantInvoiceNumber: tranId, 
+	_executeTime: 2023-06-18T10:22:31:623 GMT+0600
+)
+```
+### Error Handling
+The methods mentioned above may throw a `BkashFailure` exception in case of an error. You can catch and handle the exception using a try-catch block:
+```
 try {
-  final bkashPaymentResponse = await flutterBkash.pay(
-    context: context,
-    amount: double.parse(amount),
-    marchentInvoiceNumber: "tranId",
-  );
-
-  print(bkashPaymentResponse);
-} on BkashFailure catch (e, st) {
-  print(e.message, error: e, stackTrace: st);
-} catch (e) {
-  print("Something went wrong");
+  // Make a payment or create an agreement
+} on BkashFailure catch (e) {
+  // Handle the error
+  print(e.message);
 }
 ```
 
+Examples for see the `/example` folder.
+
+**Here is the example code**
+```
+Example Code implement here.
+```
+
 ### Importance Notes
 - Read the comments in the example of code
 - See the documents and demo checkout [bKash API Specifications](https://developer.bka.sh/v1.2.0-beta/reference), [bKash Payment Checkout Demo](https://merchantdemo.sandbox.bka.sh/frontend/checkout)
-<!-- - **intent** - it would be 'sale' or 'authorization' -->
-<!-- - Payment status return as 'paymentSuccess', 'paymentFailed', 'paymentError', 'paymentClose', find on this keyword of the payment status, then you get the data of response on specific status. -->
 
 
 ## Contributing
@@ -86,4 +158,4 @@ Contributions to the **flutter_bkash** package are welcome. Please note the foll
 
 flutter_bkash package is licensed under the [BSD 3-Clause License](https://opensource.org/licenses/BSD-3-Clause).
 
-Copyright 2022 [Codeboxr.com Team](https://codeboxr.com/team-codeboxr/). We are not affiliated with bKash and don't give any guarantee.
+Copyright 2023