added ci pipeline

.gitlab-ci.yml

@@ -0,0 +1,18 @@
+stages:
+  - publish
+
+publish-docker-container:
+  image: docker:latest
+  stage: publish
+  services:
+    - docker:dind
+  before_script:
+    - docker login -u "$REGISTRY_USER" -p "$REGISTRY_PASSWORD"
+  script:
+    - |
+      docker build --pull -t "$REGISTRY_IMAGE:latest" .
+      docker push "$REGISTRY_IMAGE:latest"
+#      docker build --pull -t "$CI_REGISTRY_IMAGE/$DOCKER_IMAGE_NAME:$CI_COMMIT_TAG" .
+#      docker push "$CI_REGISTRY_IMAGE/$DOCKER_IMAGE_NAME:$CI_COMMIT_TAG"
+  rules:
+    - if: $CI_COMMIT_TAG  # Runs the job only when a tag is created