I have a program coordinator for a course I plan to teach who wants to change the "Introduction to Web Development" course from using PHP to Ruby (I assume he means Ruby on Rails). His justification is that Ruby "is the future of web development". Because we can't argue about the future, only trends, I'm hoping to build an argument against this instead based on "teach-ability".
My personal experience in learning both PHP and Ruby on Rails is that PHP was more natural to ease into, simply because you can start inserting code wherever you need to and gradually improve your code structure and organization from that point forward. Ruby on Rails however requires a significantly sharper learning curve on code structure and organization (in my opinion). However, I learned Ruby on Rails much later in my programming career, so it was much easier to pick up than a first time student.
So my question is, what language would be more appropriate to teach a beginner course on web development given those two options?