gem install rails does not install rails
root@li44-48:/# gem install rails
Successfully installed rails-3.2.1
1 gem installed
Installing ri documentation for rails-3.2.1...
Installing RDoc documentation for rails-3.2.1...

root@li44-48:/# rails
-bash: rails: command not found

RubyGems Environment:
  - RUBYGEMS VERSION: 1.8.15
  - RUBY VERSION: 1.9.3 (2011-10-30 patchlevel 0) [i686-linux]
  - INSTALLATION DIRECTORY: /usr/lib/ruby/gems/1.9.1
  - RUBY EXECUTABLE: /usr/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-linux
  - GEM PATHS:
     - /usr/lib/ruby/gems/1.9.1
     - /root/.gem/ruby/1.9.1
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://rubygems.org/

sudo gem install rails