Hey, i am a website designer too, but i also have experience in PHP and ASP and others, but what i think is,
if you really newbie in Ruby, you're gonna need some time to understand, meantime if you were an ex-C/C++,PHP
deveolopper, there is no need to wait, you already a Ruby programmer.
for my case: i used Ruby not for websites, i used it for doing some network tests and its just fantastic.
Ruby is a scripting language that executes on the server-side. SQL is a language that allows Ruby to communicate with the database. In order to build working websites, however, you will also need to understand at least HTML (Hypertext Markup Language). HTML, unlike Ruby, is not a scripting language; it is a markup language. This means that it describes the data that should be displayed on the client-side.
In total, that is 5 languages that you would have to be familiar with: