title: Remove ActiveRecord in Rails 3
body: <p>Now that Rails 3 beta is out, I thought I'd have a look at rewriting an app I have just started work on in Rails 3 beta, both to get a feel for it and get a bit of a head-start. The app uses MongoDB and MongoMapper for all of its models and therefore has no need for ActiveRecord. In the previous version, I am unloading activerecord in the following way:</p>
  
  <pre><code>config.frameworks -= [ :active_record ]    # inside environment.rb
  </code></pre>
  
  <p>In the latest version this does not work - it just throws an error:</p>
  
  <pre><code>/Library/Ruby/Gems/1.8/gems/railties-3.0.0.beta/lib/rails/configuration.rb:126:in
    `frameworks': config.frameworks in no longer supported. See the generated 
    config/boot.rb for steps on how to limit the frameworks that will be loaded 
    (RuntimeError)
   from *snip*
  </code></pre>
  
  <p>Of course, I have looked at the boot.rb as it suggested, but as far as I can see, there is no clue here as to how I might go about unloading AR. The reason I need to do this is because not only is it silly to be loading something I don't want, but it is complaining about its inability to make a DB connection even when I try to run a generator for a controller. This is because I've wiped <code>database.yml</code> and replaced it with connection details for MongoDB in order to use <a href="http://gist.github.com/232953" rel="noreferrer">this gist</a> for using database.yml for MongoDB connection details. Not sure why it needs to be able to initiate a DB connection at all just to generate a controller anyway....</p>
  
  <p>Is anyone aware of the correct Rails 3 way of doing this?</p>