Merge branch 'master' of https://git.mylab.th-luebeck.de/cloud-native/lab-containerization

.gitlab-ci.yml

+stages:
+    - test
+    - build
+
+test:
+    stage: test
+    image: docker:19.03.12
+    script:
+    - docker build -t web:test .
+    - docker run -d -p 80:80 web:test
+    - curl http://localhost
+
+build:
+    stage: build
+    services:
+    - docker:dind
+    script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build -t $CI_REGISTRY_IMAGE/web:$CI_COMMIT_SHA -t $CI_REGISTRY_IMAGE/web:latest .
+    - docker push $CI_REGISTRY_IMAGE/web:$CI_COMMIT_SHA
+    - docker push $CI_REGISTRY_IMAGE/web:latest