I've recently started noticing the same trend in Ruby on Rails development as Java development was 10 years ago. Everyone who is anyone is jumping into it. From engineers to musicians. While its nice to have a lot of developers, the end quality remains elusive. So if you're thinking about picking up Rails, ask yourself this:
Are you in it for the money or are you in it for the passion?
If you're for the former, all the best to you, I really dont have much to say after that.
If you're the latter, then I suggest you strategize before becoming a code monkey, a list I'd recommend is:
1. Read the basics - ie know what Ruby is first and then pick up on the basics of Ruby on Rails
2. Write a simple application - but dont leave the 'magic' work under the hood without understanding it. Rip it apart, figure out why something works and why it doesnt work. Scaffold's and ActiveRecord in Rails make web development look like a walk in the park. But only those developers who understand what happens under the hood make it past the standard websites and onto the more interesting and challenging tasks of scalability and security.
3. Keep returning back to the basics. A sky scrapper would fall if its foundations were to be eroded. Dont let that happen to you.
4. Be active on GitHub. Nothing beats being the person who writes code that hundreds or thousands of other developers get to use. And you'll learn meta-programming in the process too!
5. Take on energetic developers as your proteges. Every now and then you'll get a question that'll make you think even when your current projects doesnt.
6. Avoid the 'I am god' syndrome. No matter how good you are, there will always be someone better. And nobody likes a snob anyway!