title: Why "bundle update" doesn't update the Gemfile to use Rails 3.0.5?
body: <p>I tried using <code>bundle update</code> for a Rails 3.0.0 project I created, expecting all the content in <code>Gemfile</code> (and also <code>Gemfile.lock</code>) to reflect rails 3.0.5...</p>
  
  <p>But it keep on being 3.0.0...  even if I run <code>bundle update rails</code>, it still keep on being 3.0.0</p>
  
  <p>Out of curiosity, I created a brand new Rails 3.0.0 project, and then run bundle update on it... and it still says "using rails 3.0.0", why?  And how to make <code>bundle update</code> update to 3.0.5?  (other than the obvious way to change the Gemfile by hand)</p>
  
  <p>(I even tried changing <code>sqlite3-ruby</code> to <code>sqlite3</code> in the <code>Gemfile</code>, because 3.0.5 seems to use <code>sqlite3</code> instead.  And <code>rails</code> and <code>sqlite3</code> are the only 2 gems listed in <code>Gemfile</code>)</p>