add golang books lists in other languages

ref #163

CONTRIBUTING.md

@@ -1,8 +1,9 @@
 Contribution Guidelines
 ====
 
-Add books with this format :
+## Adding a book to the main list
 
+Add books with this format:
 
 ```
 ### DATE - [BOOK NAME](BOOK URL)
@@ -17,3 +18,21 @@ BOOK DESCRIPTION
 * If book is free, add it after free books of that category and also add `*Free*` after book url.
 * Add other books in ascending date order (newest last). Books without date go at the end of the list in that category.
 * To keep track of the huge table of contents you can use a plugin like [Markdown VSCode plugin](https://marketplace.visualstudio.com/items?itemName=yzhang.markdown-all-in-one)
+
+## Adding a book in another language
+
+If a Go book exists in a language that already has a page (`gobooks/README-<lang>.md`), add it to that file using the same format as the main list. Write the book description in that language. Cover images go in `gobooks/covers/` as usual.
+
+## Adding a new language
+
+If no page exists yet for a language:
+
+1. Create `gobooks/README-<lang>.md` using the [ISO 639-1](https://en.wikipedia.org/wiki/List_of_ISO_639_language_codes) language code (e.g. `README-ja.md` for Japanese).
+2. Use the title **Go Books** translated into that language as the page heading (e.g. `# Go ブックス`).
+3. Write the introductory description in that language. Keep it simple: state that this is a complete list of Go books available in that language.
+4. List books using the same card format as the main README. All descriptions must be written in that language.
+5. For right-to-left languages (Arabic, Farsi, Hebrew, etc.), wrap the entire content in `<div dir="rtl"> ... </div>`.
+6. Add a link to the new page in the language bar at the top of `README.md`:
+   ```
+   **Other languages:** ... · [Language name in its own script](gobooks/README-<lang>.md)
+   ```