title: Change rails version used by rvm
body: <p>Here are my local gems :</p>
  
  <pre><code>$ gem list
  
  *** LOCAL GEMS ***
  
  actionmailer (4.0.0, 3.2.14)
  actionpack (4.0.0, 3.2.14)
  activemodel (4.0.0, 3.2.14)
  activerecord (4.0.0, 3.2.14)
  activerecord-deprecated_finders (1.0.3)
  activeresource (3.2.14)
  activesupport (4.0.0, 3.2.14)
  arel (4.0.0, 3.0.2)
  atomic (1.1.13)
  builder (3.1.4, 3.0.4)
  bundler (1.3.5)
  bundler-unload (1.0.1)
  erubis (2.7.0)
  hike (1.2.3)
  i18n (0.6.5)
  journey (1.0.4)
  json (1.8.0)
  mail (2.5.4)
  mime-types (1.24)
  minitest (4.7.5)
  multi_json (1.7.9)
  polyglot (0.3.3)
  rack (1.5.2, 1.4.5)
  rack-cache (1.2)
  rack-ssl (1.3.3)
  rack-test (0.6.2)
  rails (3.2.14)
  railties (4.0.0, 3.2.14)
  rake (10.1.0)
  rdoc (3.12.2)
  rubygems-bundler (1.2.2)
  rubygems-update (2.0.7)
  rvm (1.11.3.8)
  sprockets (2.10.0, 2.2.2)
  sprockets-rails (2.0.0)
  thor (0.18.1)
  thread_safe (0.1.2)
  tilt (1.4.1)
  treetop (1.4.15)
  tzinfo (0.3.37)
  </code></pre>
  
  <p>But when I type <code>rails -v</code> I get this :</p>
  
  <pre><code> $ rails -v
  Rails 4.0.0
   $ which rails
  /Users/polonium/.rvm/rubies/ruby-2.0.0-p247/bin/rails
  </code></pre>
  
  <p>How can I specify rvm to use rails version 3.2.14 ?</p>
  
  <p>Thanks in advance</p>