A junior rails developer should have
- A good grasp of Ruby
- A good grasp of the rails framework
- Experience pair programming
- An understanding of the Agile Software Development, and Test Driven Development
- Basic git (source control)
More importantly, they need to know how to reach out to the ruby community, and have developed the skill of getting stuck and learning their way through the stuckness.
I am Mike McGee, the other co-founder of Code Academy (http://codeacademy.org), and this description is pretty much exactly what our students are learning now.
Our program is project-based and centered around pair programming with Ruby on Rails as our web framework. It has been amazing to see the progress of our students in the first 8 weeks of the 12-week program.
While we may have a different focus and a different business model, if you want to talk to us about our experience it could be helpful in what you are trying to do. You can contact me at mike at codeacademy dot org