docs: add Gitlab Pages deployment example

Co-authored-by: razonyang <razonyang@gmail.com>

exampleSite/content/docs/deployment/gitlab-pages/index.md

@@ -0,0 +1,32 @@
++++
+# type = "docs"
+title = "Deploy to GitLab Pages"
+linkTitle = "GitLab Pages"
+date = 2022-08-27T10:30:23+08:00
+# description = "" # Used by description meta tag, summary will be used instead if not set or empty.
+featured = false
+draft = false
+comment = true
+toc = true
+reward = true
+pinned = false
+carousel = false
+categories = ["Deployment"]
+tags = ["GitLab Pages", "GitLab CI"]
+series = ["Docs"]
+images = []
++++
+
+This article explains how to deploy sites to [GitLab Pages](https://docs.gitlab.com/ee/user/project/pages/) using GitLab CI.
+
+<!--more-->
+
+## Workflow
+
+Create `.gitlab-ci.yml` at the root of your site with the following contents:
+
+```yaml
+{{% code/deployment-gitlab-pages-ci %}}
+```
+
+> See also [Starter Template GitLab Pages Configuration](https://github.com/razonyang/hugo-theme-bootstrap-skeleton/blob/main/.gitlab-ci.yml)。

exampleSite/content/docs/deployment/overview/index.md

@@ -62,6 +62,7 @@ This step depends on the which deployment methods you use.
 1. [GitHub Pages]({{< ref "docs/deployment/github-pages" >}})
 1. [Netlify]({{< ref "docs/deployment/netlify" >}})
 1. [Cloudflare Pages]({{< ref "docs/deployment/cloudflare-pages" >}})
+1. [GitLab Pages]({{< ref "docs/deployment/gitlab-pages" >}})
 1. Find more on [Hosting & Deployment](https://gohugo.io/hosting-and-deployment/)
 
 ## Further Reading

exampleSite/layouts/shortcodes/code/deployment-gitlab-pages-ci.html

@@ -0,0 +1,21 @@
+image: registry.gitlab.com/pages/hugo/hugo_extended:latest
+
+variables:
+  HUGO_ENV: production
+
+default:
+  before_script:
+    - apk add --update --no-cache git go npm
+    - npm install
+    - hugo mod get -u
+
+test:
+  script:
+    - hugo --gc --minify
+
+pages:
+  script:
+    - hugo --gc --minify
+  artifacts:
+    paths:
+      - public