docs: append custom-response docs

Author: WittBulter

README.md

@@ -7,6 +7,8 @@ the best practice of building Koa2 with TypeScript. [中文](/README_CN.md)
 1. clone repo. `git clone [email protected]:DhyanaChina/koa2-typescript-guide.git`
 2. install dependencies. `npm i`
 3. configuring database information.
+4. the docs about `koa-custom-response`，plaese see: [koa-custom-response](https://github.com/DhyanaChina/koa-custom-response)
+
 
 ### catalog
 

README_CN.md

@@ -7,6 +7,7 @@
 1. clone 项目. `git clone [email protected]:DhyanaChina/koa2-typescript-guide.git`
 2. 安装依赖. `npm i`
 3. 配置你的数据库信息，在 `config/connection.ts` 中。（不使用数据库请移除相关代码）
+4. 有关 `koa-custom-response` 文档，请看这里：[koa-custom-response](https://github.com/DhyanaChina/koa-custom-response)
 
 ### 目录