README.md in veritrans-2.4.0 vs README.md in veritrans-2.4.1

@@ -58,10 +58,13 @@
 ```ruby
 Midtrans.config.server_key = "your server key"
 Midtrans.config.client_key = "your client key"
 Midtrans.config.api_host = "https://api.sandbox.midtrans.com"
 ```
+Follow the steps given below to switch to Midtrans Production environment and to accept real payments from real customers.
+1. Change api_host URL from `https://api.sandbox.midtrans.com` to `https://api.midtrans.com`.
+2. Use Client Key and Server Key for Production environment. For more details, refer to [Retrieving API Access Keys](https://docs.midtrans.com/en/midtrans-account/overview?id=retrieving-api-access-keys).
 
 ### 2.2.A Snap
 You can see Snap example [with Sinatra](example/sinatra) and [without framework](example/snap).
 
 ```ruby
@@ -228,9 +231,97 @@
 The credit card charge result may contains `redirect_url` for 3DS authentication. 3DS Authentication should be handled on Frontend please refer to [API docs](https://api-docs.midtrans.com/#card-features-3d-secure)
 
 For full example on Credit Card 3DS transaction refer to:
 - [Sinatra example](/example/sinatra) that implement Snap & Core Api
 
+### 2.2.D Subscription API
+
+You can see some Subscription API examples [here](example/subscription), [Subscription API Docs](https://api-docs.midtrans.com/#subscription-api).
+
+#### Subscription API for Credit Card
+
+To use subscription API for credit card, you should first obtain the 1-click saved token, [refer to this docs.](https://docs.midtrans.com/en/core-api/advanced-features?id=recurring-transaction-with-subscriptions-api)
+You will receive `saved_token_id` as part of the response when the initial card payment is accepted (will also available in the HTTP notification's JSON), [refer to this docs.](https://docs.midtrans.com/en/core-api/advanced-features?id=sample-3ds-authenticate-json-response-for-the-first-transaction)
+```ruby
+require 'veritrans'
+# Set Midtrans config
+Midtrans.config.server_key = "your server key"
+Midtrans.config.client_key = "your client key"
+Midtrans.config.api_host = "https://api.sandbox.midtrans.com"
+# Prepare parameter
+parameter = {
+  "name": "monthly_subscription",
+  "amount": "14000",
+  "currency": "IDR",
+  "payment_type": "credit_card",
+  "token": saved_token_id,
+  "schedule": {
+    "interval": 1,
+    "interval_unit": "month",
+    "max_interval": 12,
+    #start_time value is just a sample time & should be replaced with a valid future time.
+    "start_time": "2022-12-20 07:00:00 +0700"
+  },
+  "metadata": {
+    "description": "Recurring payment for A"
+  },
+  "customer_details": {
+    "first_name": "John",
+    "last_name": "Doe",
+    "email": "[e-mail]",
+    "phone": "[phone]"
+  }
+}
+
+result = Midtrans.create_subscription(parameter)
+puts "Create subscription response : #{result.data}"
+
+result_get_subs = Midtrans.get_subscription(subscription_id)
+puts "get subscription response : #{result_get_subs.data}"
+
+result_enable_subs = Midtrans.enable_subscription(subscription_id)
+puts "enable subscription response : #{result_enable_subs.data}"
+
+# update subscription by subscription_id and update_subscription_param
+result_update_subs = Midtrans.update_subscription(subscription_id, update_subscription_param)
+puts "update subscription response : #{result_update_subs.data}"
+
+# disable subscription by subscription_id
+result_disable_subs = Midtrans.disable_subscription(subscription_id)
+puts "disable subscription response : #{result_disable_subs.data}"
+```
+
+#### Subscription API for Gopay
+
+To use subscription API for gopay, you should first link your customer gopay account with gopay tokenization API, [refer to this section.](#22e-tokenization-api) You will receive gopay payment token using `getPaymentAccount` API call. You can see some Subscription API examples [here](example/subscription)
+
+### 2.2.E Tokenization API
+You can see some Tokenization API examples [here](examples/tokenization), [Tokenization API Docs.](https://api-docs.midtrans.com/#gopay-tokenization)
+```ruby
+require 'veritrans'
+# Set Midtrans config
+Midtrans.config.server_key = "your server key"
+Midtrans.config.client_key = "your client key"
+Midtrans.config.api_host = "https://api.sandbox.midtrans.com"
+# Prepare parameter
+parameter = {
+  "payment_type": "gopay",
+  "gopay_partner": {
+    "phone_number": "81987654321",
+    "country_code": "62",
+    "redirect_url": "https://www.gojek.com"
+  }
+}
+
+result = Midtrans.link_payment_account(parameter)
+puts "Create pay account response : #{result.data}"
+
+result_get_account = Midtrans.get_payment_account(active_account_id)
+puts "Get pay account response : #{result_get_account.data}"
+
+result_unlink = Midtrans.unlink_payment_account(active_account_id)
+puts "Unlink response : #{result_unlink.data}"
+```
 
 ### 2.3 Handle HTTP Notification
 > **IMPORTANT NOTE**: To update transaction status on your backend/database, **DO NOT** solely rely on frontend callbacks! For security reason to make sure the status is authentically coming from Midtrans, only update transaction status based on HTTP Notification or API Get Status.
 
 Create separated web endpoint (notification url) to receive HTTP POST notification callback/webhook.