update readme

Author: SpringHerald

README.md

@@ -1,8 +1,24 @@
 # DeepCommenter
 
-The source code for DeepCommenter.
+DeepCommenter is an Intellij IDEA plugin used to generate java code comment automatically.
 
 
 
-### How to Use
+## Installation
 
+1. Download  `deepcommenter-client.jar`;
+2. Open Intellij IDEA, choose 
+   - Windows：`File` -> `Settings` -> `Plugins`;
+
+   - Mac：`IntelliJ IDEA` -> `Preferences` -> `Plugins`;
+3. choose `Install Plugin from Disk`;
+4. find the path of the jar and install it.
+5. Restart Intellij IDEA to activate the plugin.
+
+
+
+## Usage
+
+1. Select the java method you want to generate comment for;
+2. choose `Code` -> `Generate Comment`;
+3. The automatically generated comment will be inserted right above the selected code.