docs: add description of docs in contributing guide

Author: meteorlxy

docs/contributing.md

@@ -110,3 +110,17 @@ The `lint` script uses ESLint to check all source files.
 ### `yarn test`
 
 The `test` script uses Jest to run unit testings.
+
+## Documentation
+
+VuePress documentation is powered by VuePress itself, which is built from the source code of this repository.
+
+All the markdown source files are placed in `docs` directory. We are maintaining with two translations:
+
+- English (en-US) in `/` path
+- Chinese (zh-CN) in `/zh/` path
+
+We have two different deployments:
+
+- Release deployment powered by [Netlify](https://www.netlify.com). This deployment is built from the latest released version, so users will not see unreleased changes. The domain name is [https://vuepress2.netlify.app](https://vuepress2.netlify.app).
+- Developer deployment powered by [GitHub Pages](https://pages.github.com). This deployment is built from the latest commit, so developers could preview the latest changes. The domain name is [https://vuepress.github.io](https://vuepress.github.io).

docs/zh/contributing.md

@@ -110,3 +110,17 @@ VuePress 使用它自己来构建自己的文档网站。
 ### `yarn test`
 
 `test` 命令使用 Jest 来运行单元测试。
+
+## 文档
+
+VuePress 的文档是由 VuePress 自己驱动的，是由该仓库中的源码构建而来。
+
+所有的 Markdown 源文件都放置在 `docs` 目录下。我们维护了两种翻译：
+
+- 英语 (en-US) 在 `/` 路径下
+- 中文 (zh-CN) 在 `/zh/` 路径下
+
+我们部署了两套站点：
+
+- 在 [Netlify](https://www.netlify.com) 部署的 Release 版本。该站点是从最新发布的版本中构建而来，因此用户不会看到未发布的改动。域名为 [https://vuepress2.netlify.app](https://vuepress2.netlify.app)。
+- 在 [GitHub Pages](https://pages.github.com) 部署的 Developer 版本。该站点是从最新的提交中构建而来，因此开发者可以预览最新的改动。域名为 [https://vuepress.github.io](https://vuepress.github.io)。