Add automatic building through CI

.gitlab-ci.yml

+image: registry.gitlab.com/gitlab-org/cluster-integration/auto-build-image/master:stable
+variables:
+  DOCKER_TLS_CERTDIR: ""
+services:
+  - docker:19.03.5-dind
+
+stages:
+  - publish
+
+publish:
+  stage: publish
+  script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build -t $CI_REGISTRY/$CI_PROJECT_PATH .
+    - docker push $CI_REGISTRY/$CI_PROJECT_PATH
+