Add simple dockerfile and pipeline

.gitlab-ci.yml

+# This file is a template, and might need editing before it works on your project.
+
+stages: 
+ - build
+ - test
+ - deploy
+
+variables:
+  # When using dind service, we need to instruct docker, to talk with
+  # the daemon started inside of the service. The daemon is available
+  # with a network connection instead of the default
+  # /var/run/docker.sock socket. docker:19.03.1 does this automatically
+  # by setting the DOCKER_HOST in
+  # https://github.com/docker-library/docker/blob/d45051476babc297257df490d22cbd806f1b11e4/19.03.1/docker-entrypoint.sh#L23-L29
+  #
+  # The 'docker' hostname is the alias of the service container as described at
+  # https://docs.gitlab.com/ee/ci/docker/using_docker_images.html#accessing-the-services.
+  #
+  # Note that if you're using GitLab Runner 12.7 or earlier with the Kubernetes executor and Kubernetes 1.6 or earlier,
+  # the variable must be set to tcp://localhost:2376 because of how the
+  # Kubernetes executor connects services to the job container
+  # DOCKER_HOST: tcp://localhost:2376
+  #
+  # Specify to Docker where to create the certificates, Docker will
+  # create them automatically on boot, and will create
+  # `/certs/client` that will be shared between the service and job
+  # container, thanks to volume mount from config.toml
+  DOCKER_TLS_CERTDIR: "/certs"
+  DOCKER_DRIVER: overlay
+
+
+.docker-build:
+  image: docker:19.03
+  services: 
+    - docker:19.03-dind
+  before_script:
+    - docker version
+    - docker login -u "$DOCKER_HUB_USER" -p "$DOCKER_HUB_PASSWORD" $DOCKER_HUB
+  script:
+    - docker build -t unibasme/bambirds-testing:$VERSION
+    - docker push unibasme/bambirds-testing:$VERSION
+    
+
+
+docker-build-master:
+  # Official docker image.
+  stage: build
+  extends:
+    .docker-build
+  variables:
+    VERISON: latest
+  only:
+    - master
+
+docker-build-branches:
+  # Official docker image.
+  stage: build
+  extends:
+    .docker-build
+  variables:
+    VERSION: $CI_COMMIT_REF_SLUG
+  except:
+    - master
+  only:
+    - branches
+
+docker-build-tags:
+  stage: build
+  extends: 
+    .docker-build
+  variables:
+    VERSION: $CI_COMMIT_REF_NAME
+  only: 
+    - tags
+

Dockerfile

+FROM openjdk:8-jdk
+
+LABEL maintainer="Felix Haase <felix.haase@stud.uni-bammberg.de>"
+
+RUN set -eux; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends \
+		swi-prolog; \
+	rm -rf /var/lib/apt/lists/*
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