If you’re a developer, would you use a site to generate a new Rails app? It’s like doing the rails new command but in the browser with additional features.
The idea is when you visit the site, you will fill out some kind of a wizard. For example, the site allows you to select Ruby version you want to use, Rails version, you can also tick the database you want to use, templating tool to use e.g Haml or ERB. Test framework, CSS framework etc. At the end of the form, you can download the generated app in zip.
There are some tools already out there like the built-in Rails Templates, but you have to write it on your own and at the same time, maintain it to keep up with the updates.