[ActiveRecord] feature-request - Allow enable_extension to receive schema from configuration file

Currently in postgresql_adapter.rb#L380 #enable_extension(name) only is possible to inform the extension_name .

Would be intersting if we could also inform the extension_schema, I believe we have 2 options for this:

  1. Add scheme parameter like #enable_extension(name, schema).
  2. Inform an option like schema_search_path called extension_schema through database.yml configuration file.

I would like to add PR with it if the community supports it.