Yes.
…you don’t need to be a Ruby dev. Learning to code is a much bigger discussion than this, but you should at least understand enough HTML to make a change to a webpage. If I bump into a student carrying a portfolio of chalk drawings and they ask, should I learn to code, I’ll reply yes. If nothing else they will be able put those chalk drawings on the internet
I don’t think that it is a requirement, but you are much more likely to get a job as a designer if you have past experience of being a developer – It certainly helped me develop my knowledge of front-end design!