Inspired by this tutorial

• install Docker desktop
• install IntelliJ
• install the Docker plugin in IntelliJ

• open the project in IntelliJ
• find the docker-compose.yml and open it
• click on the two green arrows IntelliJ offers you
  
• set the tasks backend:bootJar and docker build . -t app-backend to be run before starting docker compose
• you are good to go, both db and backend should be running now. Visit localhost:5000 in you browser to verify it
• you can stop the running services at any time in the Services tab of IntelliJ

You can also start the backend without IntelliJ. Run the following commands in its root directory:

• ./gradlew bootJar
• docker build . -t app-backend
• docker-compose up -d