Add new ruby search library to community clients doc (#22765)

* Add new Ruby search lib from Artsy.

* update ruby library reference following rename

Author: Anil Bawa-Cavia

docs/community-clients/index.asciidoc

@@ -217,6 +217,9 @@ Also see the {client}/ruby-api/current/index.html[official Elasticsearch Ruby cl
 * https://github.com/ankane/searchkick[Searchkick]:
   Intelligent search made easy
 
+* https://github.com/artsy/estella[Estella]:
+  Make your Ruby models searchable
+
 The following projects appear to be abandoned:
 
 * https://github.com/wireframe/elastic_searchable/[elastic_searchable]: