title: Can't get mongoid working with Rails 4
body: <p><a href="http://mongoid.org/en/mongoid/docs/installation.html" rel="noreferrer">I followed the official tutorial</a>.</p>
  
  <p>I have sqlite3 commented out in my Gemfile as well as the following lines:</p>
  
  <pre><code>gem 'mongoid', '~&gt; 4', github: 'mongoid/mongoid'
  gem 'bson_ext'
  </code></pre>
  
  <p>However, I keep receiving the 
  <code>Specified 'sqlite3' for database adapter, but the gem is not loaded. Add gem "sqlite3" to your Gemfile.</code></p>
  
  <p>Reason seems to be that the database.yml still lists sqlite as the database. How am I supposed to get Rails to use the generated mongoid.yml? Replacing database.yml's contents with mongoid.yml doesn't seem to do the trick - I get the</p>
  
  <p><code>ActiveRecord::AdapterNotSpecified: database configuration does not specify adapter</code> error.</p>
  
  <p>Is it not compatible with Rails 4 or am I missing something simple?</p>
  
  <p>Edit: I think I'm getting warmer. I've added the adapter as 'mongoid'. Here's the contents of my database.yml now:</p>
  
  <pre><code>development:
    adapter: 'mongoid'
    # Configure available database sessions. (required)
    sessions:
      # Defines the default session. (required)
      default:
        # Defines the name of the default database that Mongoid can connect to.
        # (required).
        database: xboxie
        # Provides the hosts the default session can connect to. Must be an array
        # of host:port pairs. (required)
        hosts:
          - localhost:27017
        options:
          # Change whether the session persists in safe mode by default.
          # (default: false)
          # safe: false
  
          # Change the default consistency model to :eventual or :strong.
          # :eventual will send reads to secondaries, :strong sends everything
          # to master. (default: :eventual)
          # consistency: :eventual
  
          # How many times Moped should attempt to retry an operation after
          # failure. (default: 30)
          # max_retries: 30
  
          # The time in seconds that Moped should wait before retrying an
          # operation on failure. (default: 1)
          # retry_interval: 1
    # Configure Mongoid specific options. (optional)
    options:
      #
  test:
    sessions:
      default:
        database: xboxie_test
        hosts:
          - localhost:27017
        options:
          consistency: :strong
          # In the test environment we lower the retries and retry interval to
          # low amounts for fast failures.
          max_retries: 1
          retry_interval: 0
  
  
  # # SQLite version 3.x
  # #   gem install sqlite3
  # #
  # #   Ensure the SQLite 3 gem is defined in your Gemfile
  # #   gem 'sqlite3'
  # development:
  #   adapter: sqlite3
  #   database: db/development.sqlite3
  #   pool: 5
  #   timeout: 5000
  
  # # Warning: The database defined as "test" will be erased and
  # # re-generated from your development database when you run "rake".
  # # Do not set this db to the same as development or production.
  # test:
  #   adapter: sqlite3
  #   database: db/test.sqlite3
  #   pool: 5
  #   timeout: 5000
  
  # production:
  #   adapter: sqlite3
  #   database: db/production.sqlite3
  #   pool: 5
  #   timeout: 5000
  </code></pre>
  
  <p>Produces the error: </p>
  
  <p><code>LoadError: Could not load 'active_record/connection_adapters/mongoid_adapter'. Make sure that the adapter in config/database.yml is valid. If you use an adapter other than 'mysql', 'mysql2', 'postgresql' or 'sqlite3' add the necessary adapter gem to the Gemfile.</code></p>