Deploying a new version

Update the version in the Dockerfile to the coming version.
Commit the new Dockerfile.
Create a new tag for the new version: git tag -a <version>.
Push everything to github: git push --all && git push --tags.
Build it: gradle build.
Create a new release on github for this version. 'Release title' has to be just the version string. Attach the newly built telegram-backup.jar.
Build the docker image: docker build -t fabianonline/telegram_backup:<version> -t fabianonline/telegram_backup:latest - < DOCKERFILE.
Push the docker image: docker push fabianonline/telegram_backup.
Post a message into the telegram_backup users group.