Rails auto generates very little these days unless you ask for it.
I was reading the parent comment and some of the other comments about the mental model of a beginner. I suppose if you're first exposed to Rails and start using 'scaffold' it can generate a ton of code you'll need to grok. But once you understand the nuances of writing Rails its much faster and cleaner to just create files and go about your business. There is only 1 thing I ask Rails to generate for me and its database migrations; it handles adding the timestamp and placing it as the end of the folder, thats not something I care to think about myself.