update README

Author: genkio

Diff for: README.md

@@ -17,6 +17,11 @@ Spiderless is the backend layer of [KMPPP](https://kmppp.com), a web spider as a
 | [AWS Cloudfront](https://aws.amazon.com/cloudfront/) | CDN |
 | [AWS Route 53](https://aws.amazon.com/route53/) | DNS |
 
+
+## Architecture
+![serverless application architecture](https://user-images.githubusercontent.com/5327840/50051425-32583400-0155-11e9-8b67-a45c9acda351.png)
+
+
 ## API Endpoints
 
 ### `GET` subscriptions