Add CI to build and deploy the service

.gitlab-ci.yml

+stages:
+  - build
+  - deploy
+
+build:
+  stage: build
+  allow_failure: false
+  image:
+    name: gcr.io/kaniko-project/executor:v1.20.1-debug
+    entrypoint: [""]
+  rules:
+    - if: $CI_COMMIT_TAG
+  script:
+    - echo "{\"auths\":{\"${DOCKERHUB_REGISTRY}\":{\"auth\":\"$(printf "%s:%s" "${DOCKERHUB_REGISTRY_USER}" "${DOCKERHUB_REGISTRY_PASSWORD}" | base64 | tr -d '\n')\"}}}" > /kaniko/.docker/config.json
+    - /kaniko/executor
+      --context "${CI_PROJECT_DIR}"
+      --dockerfile "${CI_PROJECT_DIR}/Dockerfile"
+      --destination "${DOCKERHUB_REPO}:${CI_COMMIT_TAG}"
+    - |
+      cat << EOF  > deploy.env
+      DOCKER_IMAGE=${DOCKERHUB_REPO}:${CI_COMMIT_TAG}
+      EOF
+  after_script:
+    - cat deploy.env
+  artifacts:
+    reports:
+      dotenv: deploy.env
+
+.deploy:
+  stage: deploy
+  image: alpine/k8s:1.28.3
+  needs:
+    - job: build
+      artifacts: true
+  script:
+    - sed -i "s;DOCKER_IMAGE;${DOCKER_IMAGE};" kubernetes.yaml
+    - sed -i "s;HOST;${HOST};" kubernetes.yaml
+    - kubectl config use-context "frank/grpc-helloworld:${AGENT}"
+    - kubectl apply -n "${NAMESPACE}" -f kubernetes.yaml
+  artifacts:
+    paths:
+      - kubernetes.yaml
+    expire_in: 30d
+  rules:
+    - if: $CI_COMMIT_TAG
+
+deploy_staging:
+  # Deploy the current image to the staging machine.
+  extends: .deploy
+  variables:
+    NAMESPACE: howlargeisthelhc-staging
+    AGENT: stratus-staging
+    HOST: grpc-helloworld.preview.sauerburger.com
+  environment:
+    name: Staging Environment
+    url: https://grpc-helloworld.preview.sauerburger.com/
+
+deploy_production:
+  extends: .deploy
+  when: manual
+  variables:
+    NAMESPACE: howlargeisthelhc-staging
+    AGENT: stratus
+    HOST: grpc-helloworld.sauerburger.cloud
+  environment:
+    name: Production Environment
+    url: https://grpc-helloworld.sauerburger.cloud/