Add version v28 (#564)

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Reviewed-on: https://gitea.com/gitea/docs/pulls/564
Reviewed-by: bircni <[email protected]>
Co-authored-by: Lunny Xiao <[email protected]>

versioned_docs/version-28/administration/search-engines-indexation.md

@@ -0,0 +1,31 @@
+---
+date: "2019-12-31T13:55:00+05:00"
+slug: "search-engines-indexation"
+sidebar_position: 60
+aliases:
+  - /en-us/search-engines-indexation
+---
+
+# Search Engines Indexation
+
+By default your Gitea installation will be indexed by search engines.
+If you don't want your repository to be visible for search engines read further.
+
+## Block search engines indexation using robots.txt
+
+To make Gitea serve a custom `robots.txt` (default: empty 404) for top level installations,
+create a file with path `public/robots.txt` in the [`custom` folder or `CustomPath`](../administration/customizing-gitea.md)
+
+Examples on how to configure the `robots.txt` can be found at [https://moz.com/learn/seo/robotstxt](https://moz.com/learn/seo/robotstxt).
+
+```txt
+User-agent: *
+Disallow: /
+```
+
+If you installed Gitea in a subdirectory, you will need to create or edit the `robots.txt` in the top level directory.
+
+```txt
+User-agent: *
+Disallow: /gitea/
+```