When an unsuccessful request is returned, there are some special pages that a Hanami application presents to users.
These pages have a generic graphic and some basic information like the HTTP status code and the message.
Hanami allows us to customize them on a per-application basis.
We just need to create a template with the corresponding HTTP code as the filename (e.g. apps/web/templates/500.html.erb).
From then on, all 500 errors (Internal Server Error) will be presented using that template (like for an exception that is not rescued).
A template for a custom error page MUST be named after the HTTP code that it targets.
Example: 500.html.erb for Internal Server Error (500).
A template for a custom error page MUST be placed under the templates directory of the application.