Add the new external maintainer for the ruby/rails (#291)

Author: brunoocasali

resources/tiers.md

@@ -116,6 +116,7 @@ Here is the list of the external collaborators that help us:
 - **[@mmachatschek](https://github.com/mmachatschek)**: [`meilisearch-php`](https://github.com/meilisearch/meilisearch-php), [`laravel/scout`](https://github.com/laravel/scout)
 - **[@norkunas](https://github.com/norkunas)**: [`meilisearch-php`](https://github.com/meilisearch/meilisearch-php), [`meilisearch-symfony`](https://github.com/meilisearch/meilisearch-symfony)
 - **[@sanders41](https://github.com/sanders41)**: [`meilisearch-python`](https://github.com/meilisearch/meilisearch-python), [`docs-scraper`](https://github.com/meilisearch/docs-scraper)
+- **[@ellnix](https://github.com/ellnix)**: [`meilisearch-ruby`](https://github.com/meilisearch/meilisearch-ruby), [`meilisearch-rails`](https://github.com/meilisearch/meilisearch-rails)
 
 ## FAQ