title: Could not find gem 'sqlite3 (>= 0) ruby'
body: <p>I am learning Ruby on Rails and I followed the installation of RVM and Rails from Ryan Bigg's blog and the Agile Wed Development book. This has worked previously on my PC at home, but at work it gives me the error:</p>
  
  <pre><code>depot$ rails -v
  Could not find gem 'sqlite3 (&gt;= 0) ruby' in the gems available on this machine.
  Run `bundle install` to install missing gems.
  </code></pre>
  
  <p>I am trying to generate a scaffold but this is what i get:</p>
  
  <pre><code>depot$ rails generate scaffold Product \ title:string description:text image_url:text price:decimal
  Could not find gem 'sqlite3 (&gt;= 0) ruby' in the gems available on this machine.
  Run `bundle install` to install missing gems.
  </code></pre>
  
  <p>I have sqlite3 installed, RVM 1.9.2-p320, and running on Ubuntu 11.04.</p>
  
  <p>Any ideas what can be causing this and how to fix it?</p>