Update README.md

Author: hongcaiyu

README.md

@@ -9,8 +9,11 @@ This SDK enables you to create and modify xmind(`.xmind`) files, and it's writte
 Supported Platforms:
 
 - iOS 9+
+
 - macOS 10.11+
 
+  
+
 ## Structure of XMind files
 
 XMind file is a zip file which contains several components, including manifest, metadata, sheets and resources.
@@ -23,6 +26,46 @@ Sheets contains all of the topics that belong to the each sheets(canvas).
 
 Manifest lists primary files that contained in this xmind file.
 
+
+
+## Fast Creating
+
+When you just wanna create a xmind file easily. Use the DSL.
+
+```swift
+import XMindSDK
+
+...
+...
+
+let wb = try! workbook {
+    topic(title: "Apple") {
+        topic(title: "Hardware") {
+            topic(title: "iPhone") {
+                topic(title: "iPhone 6")
+                topic(title: "iPhone 7 Plus")
+                topic(title: "iPhone 8")
+                topic(title: "iPhone XS Max")
+            }
+            topic(title: "Mac") {
+                topic(title: "MacBook Pro")
+                topic(title: "Mac mini")
+                topic(title: "Mac Pro")
+            }
+        }
+        
+        topic(title: "Software") {
+            topic(title: "Xcode")
+            topic(title: "Siri")
+        }
+    }
+}
+
+try wb.save(to: filePath)
+```
+
+
+
 ## Usage
 
 If you create a new xmind file, you can directly operate sheets and topics after initializing a `Workbook` instance that represents a xmind file.