add a gitlab CI/CD file

Co-authored-by: Roudy Dagher <rdagher@users.noreply.github.com>

add ci.inria tags to use shared runners

specify image in CI/CD

.gitlab-ci.yml

+image: docker:20.10.16
+services:
+  - docker:20.10.16-dind
+
+default:
+  tags:
+    - ci.inria.fr
+    - small
+
+stages:
+  - build
+  - release
+  # - deploy
+
+variables:
+  CONTAINER_TEST_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
+  CONTAINER_RELEASE_IMAGE: $CI_REGISTRY_IMAGE:latest
+
+before_script:
+  - docker login -u $CI_REGISTRY_USER -p $CI_JOB_TOKEN $CI_REGISTRY
+
+build-image:
+  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
+
+# deploy-image:
+#   stage: deploy
+#   script:
+#     - ./deploy.sh
+#   only:
+#     - master
+#   environment: production
\ No newline at end of file