add inital language (ar,ja,ru,zh-CN) and implement tools to auto-update

Readme.md

@@ -54,6 +54,27 @@ Translating is easy and fun:
 * Grey bullet=missing, Green bullet=done
 * For each grey bullet, translate the English text to your language.
 
+## Add new language entry if not exists
+
+1. Contact AnkiDroid Org admin to add new language entry on Crowdin
+2. Clone this repository
+3. Open [theme/head.hbs](theme/head.hbs) file in text editor
+4. Add language entry in head.hbs, for e.g. "ja": "日本語"
+
+```html
+<script>
+    let book_lang = {
+        "ar": "العربية",
+        "ja": "日本語",
+        "ru": "Русский",        
+        "zh-CN": "简体中文",
+                            // <------ add new language entry here 
+    };
+</script>
+```
+5. Commit changes and create pull request to ankidroiddocs
+6. Update translations on Crowdin
+
 ### Building a Translation
 
 To use the `po/xx.po` file for your output, run the following command: