Update Documentation

Author: psimanta

README.md

@@ -11,7 +11,28 @@ npm i ssl-commerz-node
 ```js
 const SSLCommerz = require('ssl-commerze-node');
 const PaymentSession = SSLCommerz.PaymentSession;
+// For live payment set first parameter `false` and for sandbox set it `true`
 const payment = new PaymentSession(true, YOUR_STORE_ID, STORE_STORE_PASS)
-// For live payment set first parameter false
 
-```
+// Set the urls
+payment.setUrls({ 
+    success: 'yoursite.com/success', // If payment Succeed
+    fail: 'yoursite.com/fail', // If payment failed
+    cancel: 'yoursite.com/cancel', // If user cancel payment
+    ipn: 'yoursite.com/ipn' // SSLCommerz will send http post request in this link
+});
+
+// Set order details
+payment.setOrderInfo({
+    total_amount: 1570, // Number field
+    currency: 'BDT', // Must be three character string
+    tran_id: 'ref12345667', // Unique Transaction id 
+    emi_option: 0 // 1 or 0,
+    multi_card_name: 'internetbank', // Do not Use! If you do not customize the gateway list, 
+    allowed_bin: '371598,371599,376947,376948,376949', // Do not Use! If you do not control on transaction 
+    emi_max_inst_option: 3,  // Max instalment Option
+    emi_allow_only: 0 // Value is 1/0, if value is 1 then only EMI transaction is possible
+});
+
+```
+See this for details: https://developer.sslcommerz.com/doc/v4/#ready-the-parameters

package.json

@@ -12,6 +12,10 @@
   },
   "author": "Simanta Paul simanta.paul.26@gmail.com",
   "license": "ISC",
+  "keywords": [
+    "nodejs",
+    "sslcommerz"
+  ],
   "dependencies": {
     "form-data": "^4.0.0",
     "node-fetch": "^2.6.1"