chore: update readme

Author: ulivz

README.md

@@ -1,7 +1,28 @@
-# vuepress-plugin-blog
+# @vuepress/plugin-blog
 
-> Blog plugin for VuePress
+> Official blog theme for VuePress. 
 
-## License
+Note that this plug-in has been deeply integrated into [@vuepress/theme-blog](https://github
+.com/ulivz/vuepress-theme-blog).
 
-MIT © ULIVZ
+## Install
+
+```bash
+yarn add -D @vuepress/plugin-blog
+# OR npm install -D @vuepress/plugin-blog
+```
+
+## Usage
+
+```javascript
+module.exports = {
+  plugins: ['@vuepress/blog'] 
+  // Please head documentation to see the available options.
+}
+```
+
+## Author
+
+**@vuepress/theme-blog** © [ULIVZ](https://github.com/ulivz), Released under the [MIT](./LICENSE) License.<br>
+
+> [github.com/ulivz](https://github.com/ulivz) · GitHub [@ULIVZ](https://github.com/ulivz) · Twitter [@_ulivz](https://twitter.com/_ulivz)