setting up a git repo at your domain hosting provider..
pre requisite - git should be installed there

follow
http://railstips.org/blog/archives/2008/11/23/gitn-your-shared-host-on/

Install random req tools on EC2 Amazon AWS

http://www.paul-norman.co.uk/2011/02/core-software-installation/

also see

http://codingthis.com/platforms/linux/how-to-point-a-domain-to-an-amazon-ec2-virtual-server/

ubuntu apache passenger

https://help.ubuntu.com/community/RubyOnRails#Configure Apache

Capistrano for dummies

the bare basics..
http://www.softiesonrails.com/2007/4/5/the-absolute-moron-s-guide-to-capistrano
http://teachmetocode.com/screencasts/basic-deployment-with-capistrano/