Add Feature Docker support and externalize config via environment

[sidhantmourya]

Introduced Dockerfile and docker-compose.yml for containerized deployment, including a MySQL service. Updated application.properties to use environment variables for configuration, enabling easier deployment and configuration management.

[Copilot]

Pull Request Overview

Adds containerization support with Docker and externalizes application configuration via environment variables for easier deployment management.

• Externalize Spring configuration properties to environment variables
• Introduce Dockerfile for building the application image
• Add docker-compose setup including MySQL service and network

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/main/resources/application.properties	Switched hard-coded Spring properties to use ${…} env variables
docker/docker-compose.yml	Defined course-app and mysql-db services with environment-driven config
Dockerfile	Created image build steps and entrypoint for container

Comments suppressed due to low confidence (1)

docker/docker-compose.yml:13

• Use the MySQL service hostname (mysql-db) instead of localhost to ensure the application container can resolve and connect to the database.

      SPRING_DATASOURCE_URL: jdbc:mysql://localhost:3306/course-app-api

[Copilot]

Remove the unintended leading space after = so the environment variable value isn't prefixed with a space.

Suggested change

	spring.datasource.name= ${SPRING_DATASOURCE_NAME}
	spring.datasource.name=${SPRING_DATASOURCE_NAME}

[Copilot]

The exposed port 8081 does not match the 8080 port mapping in docker-compose. Align these (e.g., expose 8080) to avoid connectivity issues.

Suggested change

	EXPOSE 8081
	EXPOSE 8080