How to include extern env.properties?

Question

Here is my Dockerfile:

FROM openjdk:11-jre
COPY build/libs/project-lion-api-0.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java", "-jar", "app.jar"]

My Spring resources directory contains:

../src/../resources in ..

application.yml
application-dev.yml
application-test.yml
env.properties <-- git ignore

This env file contains sensitive information, such as database passwords. So the file is not uploaded to Git.

However, the server does not work because the env.properties file was not found after docker deploy. How do I include env.properties?