add instructor into readme

Author: LinuxSuRen

README.md

@@ -13,11 +13,19 @@ Run with Maven command:
 mvn spring-boot:run
 ```
 
+Run in container:
+
+```shell
+docker run -p 8080:8080 ghcr.io/devops-ws/learn-springboot:master
+```
+
 Change the listen port:
 ```shell
 java -jar demo.jar --server.port=8081
 ```
 
+The default username is `admin`, and password is: `123456`.
+
 ## OpenAPI definition
 You can visit it via: http://localhost:8080/v3/api-docs