update readme

README.md

@@ -8,10 +8,14 @@ chassis <ˈʃæsi>  n. 底盘，底架
 
 1. 微服务模板代码
 2. 可观测 Observability 
-   1. Metrics (Statsd + Prometheus + Grafana)
+   1. Metrics 
-   2. Logging (ELK)
+       - Statsd + Prometheus + Grafana) 
-   3. Tracing (TODO, Maybe OpenTelemetry)
+   2. Logging 
-   4. Error Reporting（Sentry)
+       - ELK
+   3. Tracing 
+       - TODO, Maybe OpenTelemetry
+   4. Error Reporting
+       - Sentry
 3. 数据存储相关 utils
    1. Sqlalchemy
       - 连接池