How to install rails 3? what are the versions of rvm postgresql coffee script needed?

[Exequiel]

I already installed 4.1.1 rails version,
but i need to down grade my version of ruby into rails 3, how can i downgarade or install rails 3 and what are the versions of RVM, posgresql, coffescript etc that i need to install after installing rails 3 and set my default version into rails 3?

Thnak you for your replies... i hope somebody help me here, , thanks.

[invention]

Install rail 3 and then try to install postgresql, etc, you will come to know which versions are required.

[Exequiel]

thank you for your reply, your advice is right but i already made the solutions for this problem last week. hehe. your reply are so appreciated. :) Thank you. . .