Do not worry about doing RoR on a server until you know enough about it to make that investment. RoR c an easily be developed on your own computer. The built-in server is more than adequate for learning and development.
When you have a finished application that you want to deploy,.then it’s time to worry about this. I don’t recommend thinking about the deployment issue when you’re first starting out.
Deploying Rails isn’t that difficult but the shared hosts who don’t specialize in Rails (read: don’t know how Rails actually works) make it much harder and painful for new developers than it needs to be.