Add markup for foldable text

Author: jaychsu

README.md

@@ -138,3 +138,19 @@ _Image with alt :_
 ![picture alt](http://www.brightlightpictures.com/assets/images/portfolio/thethaw_header.jpg "Title is optional")
 
     Markup : ![picture alt](http://www.brightlightpictures.com/assets/images/portfolio/thethaw_header.jpg "Title is optional")
+
+Foldable text:
+
+<details>
+  <summary>Title 1</summary>
+  <p>Content 1 Content 1 Content 1 Content 1 Content 1</p>
+</details>
+<details>
+  <summary>Title 2</summary>
+  <p>Content 2 Content 2 Content 2 Content 2 Content 2</p>
+</details>
+
+    Markup : <details>
+               <summary>Title 1</summary>
+               <p>Content 1 Content 1 Content 1 Content 1 Content 1</p>
+             </details>