adding a readme

Author: jycouet

apps/svelte.dev/scripts/sync-packages/README.md

@@ -0,0 +1,19 @@
+# sync-packages
+
+This script syncs the packages metadata from NPM & GitHub.
+
+## Usage
+
+```bash
+pnpm sync-packages
+```
+
+## Notes
+
+- All packages `names` are in `FEATURED` and `SV_ADD` of [packages-meta.ts](apps/svelte.dev/src/lib/packages-meta.ts) file.
+
+If you want to add or remove a package, you need to update these 2 objects and run the script again (it will update the json files in the `src/lib/server/generated/registry` directory).
+
+- [sync-packages.yml](/.github/workflows/sync-packages.yml) is responsible for running the script regularly and update all metadata (it can also be triggered manually).
+
+- Ambassadors and maintainers are curating the list of packages.