The swagger documentation gem rswag contains the library Swagger UI. This allows your generated documentation to be viewable from your webserver.
It's great out of the box but is also more configurable than the gem's documentation would lead you to believe.
You have direct access to things like authentication but anything deeper than that can be controlled via a configuation object.
Rswag::Ui.configure do |c| c.config_object["showExtensions"] = true end
Utilize the configuration's
config_object. It is just a hash that you can set with keys that match available options found in Swagger UI's configuration docs