Removing database.yml when using Mongoid in Rails 3.2

I just began a new rails project and wanted to use MongoidDB thru the Mongoid gem. Following the instructions on the Mongoid site, I added the following lines to my Gemfile:

gem "mongoid", "~> 2.4"
gem "bson_ext", "~> 1.5"

I then proceeded to removing my database.yml file as per the instructions here. My application.rb file now looks like so:

require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "rails/test_unit/railtie"
require "sprockets/railtie" # Uncomment this line for Rails 3.1+

Now, when I use rails s to start my server in development, I get the following errors:

~/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.2.0/lib/rails/railtie/configuration.rb:85:in `method_missing': undefined method `active_record' for #<Rails::Application::Configuration:0x007ff38b20d0b0> (NoMethodError)

I tried looking for a solution, but it seems no one has yet to come across my problem. Am I doing something wrong? Is this caused by the recent Rails 3.2 update?

Thanks for your help!

UPDATE (Jan 26): Based on the info from Dylan Markow, I used the terminal command

grep -r active_record config/

And put any refrences to active_record in comment blocks.

I have a simple controller with one action that does not even hit the database yet. When I access the action via browser I get

ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished):
  activerecord (3.2.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:374:in `retrieve_connection'
  activerecord (3.2.0) lib/active_record/connection_adapters/abstract/connection_specification.rb:168:in `retrieve_connection'
  activerecor