This will install rbenv, a ruby version manager and ruby 2.0.0-p0 , rails in Ubuntu

rbenv_ruby

/* Requirements install git and curl */

/* installing rbenv */
 
curl https://raw.github.com/fesplugas/rbenv-installer/master/bin/rbenv-installer | bash

/* add this instead of generated stuff "PREPEND" the echo wordings to ~/.profile */

echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.profile
echo 'eval "$(rbenv init -)"' >> ~/.profile
source ~/.profile
 
/* make sure it works after another login you should see something like 

/home/vysakh/.rbenv/bin:/home/vysakh/.rbenv/shims:/home/vysakh/.rbenv/bin:

*/

env $PATH

/*to install sqlite and other dependencies*/

sudo apt-get install libreadline-dev libssl-dev zlib1g-dev build-essential bison openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-0 libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev ncurses-dev

/* for readline to make rails c along with installing ruby */

CONFIGURE_OPTS="--with-readline-dir=/usr/include/readline" rbenv install 2.0.0-p0 

/* making it global */
rbenv global 2.0.0-p0
 
gem install bundler --no-ri --no-rdoc

/* you need to run "rbenv rehash" after every gem installation" */ 

rbenv rehash

/* installing rails */
gem install rails
rbenv rehash