The classic first project for a Rails programmer to tackle is a blog. Since the first demonstration screencasts, the "15 Minute Blog" has become infamous. A blog is a fitting first project: it's a simple database-driven site that's quite easy to build incrementally.
This tutorial series is written for Ruby on Rails version 2.1. Though everything in these tutorials may work on later or earlier versions, it's recommended that you install version 2.1 of the Ruby on Rails gem. To install the specific version of the Ruby on Rails gem (and all its dependencies), run the following command.
$ gem install rails --version "= 2.1.0"
If newer versions have been released since this article was written, this will downgrade Rails to the earlier version. If you have an older version installed, this will upgrade Ruby on Rails to version 2.1.