DEVEXP-587 : Update README to include an example for connecting to MarkLogic Cloud

Author: anu3990

README.md

@@ -37,9 +37,9 @@ collection into the Documents database using MarkLogic's built-in REST server
 at port 8000:
 
 ```javascript
-var marklogic = require('marklogic');
+const marklogic = require('marklogic');
 
-var db = marklogic.createDatabaseClient({
+const db = marklogic.createDatabaseClient({
   host:     'localhost',
   port:     '8000',
   database: 'Documents',
@@ -48,6 +48,14 @@ var db = marklogic.createDatabaseClient({
   authType: 'DIGEST'
 });
 
+// For MarkLogic Cloud
+const db = marklogic.createDatabaseClient({
+    apiKey:   'changeme',
+    host:     'example.beta.marklogic.com',
+    authType: 'cloud',
+    basePath: '/marklogic/test'
+});
+
 db.createCollection(
   '/books',
   {author: 'Beryl Markham', ...},