env property added in docker file , readme updated

Dockerfile

@@ -21,7 +21,8 @@ RUN chmod +x mvnw
 
 # Install dependencies on into image
 RUN ./mvnw dependency:go-offline
-
+# This will be overriden if defined in docker compose file or during build if passed to do so.
+ENV APP_ENV_NAME qat
 
 # copy all of our code into image
 #copy src file to app folder inside the image

README.md

@@ -1,5 +1,10 @@
 ## Explanation and Information
 
+- Sometimes, to build image (caching effect will not show the recent changes sometimes)
+```bash
+   docker-compose up --build 
+```
+
 #### Note : For detail explanation of how to dockerize simple spring boot Java application you can visit my website at [guides to code ](https://guidestocode.com/java/how-to-dockerize-java-spring-boot-application/)
 ------------
 ### Information Keeping Web Application using Spring Boot, Data JPA, Thymeleaf and Spring  Security.

docker-compose.yml

@@ -27,11 +27,12 @@ services:
       - SPRING_DATASOURCE_USERNAME=postgres
       - SPRING_DATASOURCE_PASSWORD=_BadriPostgres1@
       - SPRING_JPA_HIBERNATE_DDL_AUTO=update
+#      - APP_ENV_NAME=uat
 
   pg_database:
 
     #official image of postgres from the docker hub, by default pulls the latest one.
-    image: postgres
+    image: postgres:16
     container_name: container_postgres_service
 
     # map the ports for postgres