When working with Rails, there are a number of useful resources that I find myself going back to frequently. I have made a list of them with a little writeup about what can be found at each link.

Model

Rails database migration guide – This guide has information about how to write a migration to create a database model.

Model validation – This guide explains what validations are and all the options to use for validating models.

Model associations – This guide explains what associations between models are and how to set them up correctly.

Querying models – This guide explains how to write calls to query the database for information stored there.

View

Form helper – This guide is all about the form helper and how to create forms to accept information from the user.

Controller

Rails routing – This guide explains how the Rails router works and how to setup the routes.rb file to know where to route requests for pages.

Tutorials

codeschool.com – Code School has several good free tutorials on Ruby, Rails, and Javascript. The tutorials are easy to follow and quiz you at the end of each lesson to make sure you learned what was in the lesson before going on to the next lesson.

railstutorial.org – This was the first tutorial I did when I wanted to start learning Rails programming. The tutorial is quite good, but I recommend skipping the parts about Test Driven Development. It really confused me the first time I worked through it. Later when you have a better grasp of Rails, I’d recommend doing it again with the tests to learn how testing in Rails works.

Other

stackoverflow.com – This is one of the most useful sites for anyone doing software development. Type in a description of the problem you’re having in your program, and chances are good someone has had the same problem and other people have shared information about how to fix the problem.