Devise with MongoModel

devise.rb

# Replace relevant section in config/initializers/devise.rb

  # ==> ORM configuration
  # Load and configure the ORM. Supports :active_record (default) and
  # :mongoid (bson_ext recommended) by default. Other ORMs may be
  # available as additional gems.
  require 'devise/orm/mongomodel'

mongomodel.rb

# Save me in lib/devise/orm/mongomodel.rb

require 'mongomodel'

module MongoModel
  class Document
    extend OrmAdapter::ToAdapter

    class OrmAdapter < ::OrmAdapter::Base
      # get a list of column names for a given class
      def column_names
        klass.properties.values.map(&:name)
      end

      # @see OrmAdapter::Base#get!
      def get!(id)
        klass.find(wrap_key(id))
      end

      # @see OrmAdapter::Base#get
      def get(id)
        klass.find_by_id(wrap_key(id))
      end

      # @see OrmAdapter::Base#find_first
      def find_first(conditions = {})
        conditions, order = extract_conditions!(conditions)
        
        scope = klass.where(conditions)
        scope = scope.order(order) unless order.nil?
        scope.first
      end

      # @see OrmAdapter::Base#find_all
      def find_all(conditions = {})
        conditions, order, limit, offset = extract_conditions!(conditions)
        
        scope = klass.where(conditions)
        scope = scope.order(order) unless order.nil?
        scope = scope.limit(limit) unless limit.nil?
        scope = scope.offset(offset) unless limit.nil? || offset.nil?
        scope.all
      end

      # @see OrmAdapter::Base#create!
      def create!(attributes = {})
        klass.create!(attributes)
      end

      # @see OrmAdapter::Base#destroy
      def destroy(object)
        object.destroy if valid_object?(object)
      end
    end
  end
end

MongoModel::Document.extend Devise::Models

user.rb

class User < MongoModel::Document
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable,
  # :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  ## Database authenticatable
  property :email,              String, :default => ""
  property :encrypted_password, String, :default => ""

  validates_presence_of :email
  validates_presence_of :encrypted_password
  
  ## Recoverable
  property :reset_password_token,   String
  property :reset_password_sent_at, Time

  ## Rememberable
  property :remember_created_at, Time

  ## Trackable
  property :sign_in_count,      Integer, :default => 0
  property :current_sign_in_at, Time
  property :last_sign_in_at,    Time
  property :current_sign_in_ip, String
  property :last_sign_in_ip,    String

  ## Confirmable
  # property :confirmation_token,   String
  # property :confirmed_at,         Time
  # property :confirmation_sent_at, Time
  # property :unconfirmed_email,    String # Only if using reconfirmable

  ## Lockable
  # property :failed_attempts, Integer, :default => 0 # Only if lock strategy is :failed_attempts
  # property :unlock_token,    String # Only if unlock strategy is :email or :both
  # property :locked_at,       Time

  ## Token authenticatable
  # property :authentication_token, String
end