add ci

.gitlab-ci.yml

+services:
+  - docker:dind
+
+
+variables:
+  DOCKER_HOST: tcp://docker:2375
+  DOCKER_TLS_CERTDIR: ""
+
+stages:
+  - build
+
+build-image:
+  stage: build
+  image: docker
+  script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build -f Dockerfile -t $CI_REGISTRY/$CI_PROJECT_PATH .
+    - docker push $CI_REGISTRY/$CI_PROJECT_PATH:latest
+    - docker tag $CI_REGISTRY/$CI_PROJECT_PATH:latest $CI_REGISTRY/$CI_PROJECT_PATH:$CI_COMMIT_REF_NAME
+    - docker push $CI_REGISTRY/$CI_PROJECT_PATH:$CI_COMMIT_REF_NAME