Add Gitlab-CI pipeline config

.gitlab-ci.yml

+# From template at https://gitlab.com/pages/hugo
+
+default:
+  image: "${CI_TEMPLATE_REGISTRY_HOST}/pages/hugo/hugo_extended:0.128.1"
+
+variables:
+  GIT_SUBMODULE_STRATEGY: recursive  # include Hugo themes
+  HUGO_ENV: production
+
+test:
+  script:
+    - hugo
+  rules:
+    - if: $CI_COMMIT_BRANCH != $CI_DEFAULT_BRANCH
+
+pages:
+  script:
+    - hugo
+  artifacts:
+    paths:
+      - public
+  rules:
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
+  environment: production