doc: add donation info

README.md

@@ -27,6 +27,7 @@ frp is a fast reverse proxy to help you expose a local server behind a NAT or fi
   * [Rewriting the Host Header](#rewriting-the-host-header)
 * [Development Plan](#development-plan)
 * [Contributing](#contributing)
+* [Donation](#donation)
 * [Contributors](#contributors)
 
 ## What can I do with frp?
@@ -331,6 +332,18 @@ Interested in getting involved? We would like to help you!
 
 **Note: We prefer you to give your advise in [issues](https://github.com/fatedier/frp/issues), so others with a same question can search it quickly and we don't need to answer them repeatly.**
 
+## Donation
+
+If frp help you a lot, you can support us by:
+
+### AliPay
+
+![donation-alipay](/doc/pic/donate-alipay.png)
+
+### Paypal
+
+Donate money by [paypal](https://www.paypal.me/fatedier) to my account **fatedier@gmail.com**.
+
 ## Contributors
 
 * [fatedier](https://github.com/fatedier)

README_zh.md

@@ -25,6 +25,7 @@ frp 是一个高性能的反向代理应用，可以帮助您轻松地进行内
   * [修改 Host Header](#修改-host-header)
 * [开发计划](#开发计划)
 * [贡献代码](#贡献代码)
+* [捐助](#捐助)
 * [贡献者](#贡献者)
 
 ## frp 的作用
@@ -338,6 +339,18 @@ host_header_rewrite = dev.yourdomain.com
 
 **提醒：和项目相关的问题最好在 [issues](https://github.com/fatedier/frp/issues) 中反馈，这样方便其他有类似问题的人可以快速查找解决方法，并且也避免了我们重复回答一些问题。**
 
+## 捐助
+
+如果您觉得 frp 对你有帮助，欢迎给予我们一定的捐助来维持项目的长期发展。
+
+### 支付宝扫码捐赠
+
+![donate-alipay](/doc/pic/donate-alipay.png)
+
+### Paypal 捐赠
+
+海外用户推荐通过 [Paypal](https://www.paypal.me/fatedier) 向我的账户 **fatedier@gmail.com** 进行捐赠。
+
 ## 贡献者
 
 * [fatedier](https://github.com/fatedier)