How to create rails app with older version

create rails app with older version

Hi geeks, 

my rails new version is 3.2.3.
if i wanted to create new rails app with older version say 3.0.5,
i can create using the command

rails _3.0.5_ new app

but i was getting an error 
/usr/local/lib/ruby/site_ruby/1.9.1/rubygems.rb:316:in `bin_path': can't find gem railties (["3.0.5"]) with executable rails (Gem::GemNotFoundException)
	from /usr/local/bin/rails:19:in `<main>'


so

i just installed 

sudo gem install rails -v ="3.0.5"

and then 

rails _3.0.5_ new app

now its working fine 



thank you

ok thanks dev