[Rails] Ruby on Rails 3.1 Installation tutorial for Ubuntu (versions 11.04, 11.10) and Linux Mint (version 11) - download or read online if you need it

After several weeks of messing with Ruby on Rails on Ubuntu I made
this 34 pages PDF installation tutorial which covers:

- Ruby on Rails default installation (Ruby 1.9.2, Rails 3.1, WEbrick
web server, SQLite3 database)
- Ruby on Rails advanced installation (Ruby 1.9.2, Rails 3.1, Apache
web server, MySQL database)

I am total beginner with Ruby on Rails (and a beginner with Ubuntu
Linux) - coming from Windows web development - so I've made this
tutorial as detailed as possible so others like me can use it without
a problem.

You can get the PDF file from here:
http://www.mirceagoia.com/2011/11/ruby-on-rails-installation-ubuntu-linux-mint/

I will update the tutorial from time to time as new Ruby, Rails and
Ubuntu/Mint will come out (the PDF file will have the same name
always).

If you find it useful please tell to others too (in RoR groups, forums
and other social media places).

I am open to suggestions/improvements of this tutorial.

Thank you,
Mircea