update README

Author: Ace-Radom

README.md

@@ -6,12 +6,30 @@ easytimer is a web-based timer without ads
 ![](https://img.shields.io/github/languages/code-size/Ace-Radom/easytimer)
 ![](https://img.shields.io/github/license/Ace-Radom/easytimer)
 
+## Functions
+
+easytimer offers a countdown timer and a stopwatch function since v2.0.
+
+The default interface is the timer. If you need to use the stopwatch, open the sidebar and click 'Stopwatch'.
+
 ## Interface
 
 ![](images/interface.png)
 
 ## How to use
 
-You should set the length of the countdown first, and then click 'Set Time' button.
+easytimer currently provides a countdown timer and a stopwatch.
+
+- **Countdown Timer**
+
+    You should set the length of the countdown first, and then click 'Set Time' button.
+
+    After that you can start the timer, pause or reset it as you wish.
+
+- **Stopwatch**
+
+    Just like a normal stopwatch, you can start, pause and reset it.
+
+## Thanks
 
-After that you can start the timer, pause or reset it as you wish.
+- [y5nw](https://github.com/y5nw) for UI and js-program updates.