Add gitlab-ci to build docker image

.gitlab-ci.yml

@@ -0,0 +1,33 @@
+image: docker:latest
+
+variables:
+  DOCKER_HOST: tcp://localhost:2375/
+  DOCKER_DRIVER: overlay2
+  CoNTAINER_TEST_IMAGE: "$CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG"
+  CONTAINER_RELEASE_IMAGE: "$CI_REGISTRY_IMAGE:latest"
+
+services:
+  - docker:dind
+
+stages:
+  - build
+  - release
+
+before_script:
+  - docker info
+  - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" "$CI_REGISTRY"
+
+build:
+  stage: build
+  script:
+    - docker build --pull -t "$CONTAINER_TEST_IMAGE" .
+    - docker push "$CONTAINER_TEST_IMAGE"
+
+release-image:
+  stage: release
+  script:
+    - docker pull "$CONTAINER_TEST_IMAGE"
+    - docker tag "$CONTAINER_TEST_IMAGE" "$CONTAINER_RELEASE_IMAGE"
+    - docker push "$CONTAINER_RELEASE_IMAGE"
+  only:
+    - master