an_example.rb

# rails 3.1rc4
# + devise
# + mongoid
#
(rdb:1) x = User.new(:email => 'horst', :password => 'meh11111', :password_confirmation => 'meh11111', :name => "horst")
#<User _id: 4e21cc2afe208f100900000a, _type: nil, email: "horst", encrypted_password: "$2a$10$nCQyLgONN0H8PSW.BJkohOAdMZcS2nN49MdpZYOGIbdpuPYj4wBLO", remember_created_at: nil, reset_password_token: nil, reset_password_sent_at: nil, sign_in_count: 0, current_sign_in_at: nil, last_sign_in_at: nil, current_sign_in_ip: nil, last_sign_in_ip: nil, name: "horst">
(rdb:1) x.valid?
true
(rdb:1) x.email = "dieter"
"dieter"
(rdb:1) x.valid?
false
(rdb:1) x.errors.to_json
"{\"email\":[\"is invalid\"]}"

devise_initializer.rb

# Use this hook to configure devise mailer, warden hooks and so forth. The first
# four configuration values can also be set straight in your models.
Devise.setup do |config|
  # ==> Mailer Configuration
  # Configure the e-mail address which will be shown in DeviseMailer.
  config.mailer_sender = "please-change-me-at-config-initializers-devise@example.com"

  # Configure the class responsible to send e-mails.
  # config.mailer = "Devise::Mailer"

  # ==> 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/mongoid'

  # ==> Configuration for any authentication mechanism
  # Configure which keys are used when authenticating a user. The default is
  # just :email. You can configure it to use [:username, :subdomain], so for
  # authenticating a user, both parameters are required. Remember that those
  # parameters are used only when authenticating and not when retrieving from
  # session. If you need permissions, you should implement that in a before filter.
  # You can also supply a hash where the value is a boolean determining whether
  # or not authentication should be aborted when the value is not present.
  # config.authentication_keys = [ :email ]

  # Configure parameters from the request object used for authentication. Each entry
  # given should be a request method and it will automatically be passed to the
  # find_for_authentication method and considered in your model lookup. For instance,
  # if you set :request_keys to [:subdomain], :subdomain will be used on authentication.
  # The same considerations mentioned for authentication_keys also apply to request_keys.
  # config.request_keys = []

  # Configure which authentication keys should be case-insensitive.
  # These keys will be downcased upon creating or modifying a user and when used
  # to authenticate or find a user. Default is :email.
  config.case_insensitive_keys = [ :email ]

  # Configure which authentication keys should have whitespace stripped.
  # These keys will have whitespace before and after removed upon creating or
  # modifying a user and when used to authenticate or find a user. Default is :email.
  config.strip_whitespace_keys = [ :email ]

  # Tell if authentication through request.params is enabled. True by default.
  # config.params_authenticatable = true

  # Tell if authentication through HTTP Basic Auth is enabled. False by default.
  # config.http_authenticatable = false

  # If http headers should be returned for AJAX requests. True by default.
  # config.http_authenticatable_on_xhr = true

  # The realm used in Http Basic Authentication. "Application" by default.
  # config.http_authentication_realm = "Application"

  # It will change confirmation, password recovery and other workflows
  # to behave the same regardless if the e-mail provided was right or wrong.
  # Does not affect registerable.
  # config.paranoid = true

  # ==> Configuration for :database_authenticatable
  # For bcrypt, this is the cost for hashing the password and defaults to 10. If
  # using other encryptors, it sets how many times you want the password re-encrypted.
  config.stretches = 10

  # Setup a pepper to generate the encrypted password.
  # config.pepper = "6168b09be0dc1df60b4556350b52f25483f0d49c5a100faab809c44eddeab555d43893f787fc8e42101a5d5799d64e29a637fb80854972d10d1d798291a20205"

  # ==> Configuration for :confirmable
  # The time you want to give your user to confirm his account. During this time
  # he will be able to access your application without confirming. Default is 0.days
  # When confirm_within is zero, the user won't be able to sign in without confirming.
  # You can use this to let your user access some features of your application
  # without confirming the account, but blocking it after a certain period
  # (ie 2 days).
  # config.confirm_within = 2.days

  # Defines which key will be used when confirming an account
  # config.confirmation_keys = [ :email ]

  # ==> Configuration for :rememberable
  # The time the user will be remembered without asking for credentials again.
  # config.remember_for = 2.weeks

  # If true, a valid remember token can be re-used between multiple browsers.
  # config.remember_across_browsers = true

  # If true, extends the user's remember period when remembered via cookie.
  # config.extend_remember_period = false

  # If true, uses the password salt as remember token. This should be turned
  # to false if you are not using database authenticatable.
  config.use_salt_as_remember_token = true

  # Options to be passed to the created cookie. For instance, you can set
  # :secure => true in order to force SSL only cookies.
  # config.cookie_options = {}

  # ==> Configuration for :validatable
  # Range for password length. Default is 6..128.
  # config.password_length = 6..128

  # Regex to use to validate the email address
  config.email_regexp = /\A([\w\.%\+\-]+)@([\w\-]+\.)+([\w]{2,})\z/i

  # ==> Configuration for :timeoutable
  # The time you want to timeout the user session without activity. After this
  # time the user will be asked for credentials again. Default is 30 minutes.
  # config.timeout_in = 30.minutes

  # ==> Configuration for :lockable
  # Defines which strategy will be used to lock an account.
  # :failed_attempts = Locks an account after a number of failed attempts to sign in.
  # :none            = No lock strategy. You should handle locking by yourself.
  # config.lock_strategy = :failed_attempts

  # Defines which key will be used when locking and unlocking an account
  # config.unlock_keys = [ :email ]

  # Defines which strategy will be used to unlock an account.
  # :email = Sends an unlock link to the user email
  # :time  = Re-enables login after a certain amount of time (see :unlock_in below)
  # :both  = Enables both strategies
  # :none  = No unlock strategy. You should handle unlocking by yourself.
  # config.unlock_strategy = :both

  # Number of authentication tries before locking an account if lock_strategy
  # is failed attempts.
  # config.maximum_attempts = 20

  # Time interval to unlock the account if :time is enabled as unlock_strategy.
  # config.unlock_in = 1.hour

  # ==> Configuration for :recoverable
  #
  # Defines which key will be used when recovering the password for an account
  # config.reset_password_keys = [ :email ]

  # Time interval you can reset your password with a reset password key.
  # Don't put a too small interval or your users won't have the time to
  # change their passwords.
  config.reset_password_within = 2.hours

  # ==> Configuration for :encryptable
  # Allow you to use another encryption algorithm besides bcrypt (default). You can use
  # :sha1, :sha512 or encryptors from others authentication tools as :clearance_sha1,
  # :authlogic_sha512 (then you should set stretches above to 20 for default behavior)
  # and :restful_authentication_sha1 (then you should set stretches to 10, and copy
  # REST_AUTH_SITE_KEY to pepper)
  # config.encryptor = :sha512

  # ==> Configuration for :token_authenticatable
  # Defines name of the authentication token params key
  # config.token_authentication_key = :auth_token

  # If true, authentication through token does not store user in session and needs
  # to be supplied on each request. Useful if you are using the token as API token.
  # config.stateless_token = false

  # ==> Scopes configuration
  # Turn scoped views on. Before rendering "sessions/new", it will first check for
  # "users/sessions/new". It's turned off by default because it's slower if you
  # are using only default views.
  # config.scoped_views = false

  # Configure the default scope given to Warden. By default it's the first
  # devise role declared in your routes (usually :user).
  # config.default_scope = :user

  # Configure sign_out behavior.
  # Sign_out action can be scoped (i.e. /users/sign_out affects only :user scope).
  # The default is true, which means any logout action will sign out all active scopes.
  # config.sign_out_all_scopes = true

  # ==> Navigation configuration
  # Lists the formats that should be treated as navigational. Formats like
  # :html, should redirect to the sign in page when the user does not have
  # access, but formats like :xml or :json, should return 401.
  #
  # If you have any extra navigational formats, like :iphone or :mobile, you
  # should add them to the navigational formats lists.
  #
  # The :"*/*" and "*/*" formats below is required to match Internet
  # Explorer requests.
  # config.navigational_formats = [:"*/*", "*/*", :html]

  # The default HTTP method used to sign out a resource. Default is :delete.
  config.sign_out_via = :get

  # ==> OmniAuth
  # Add a new OmniAuth provider. Check the wiki for more information on setting
  # up on your models and hooks.
  # config.omniauth :github, 'APP_ID', 'APP_SECRET', :scope => 'user,public_repo'

  # ==> Warden configuration
  # If you want to use other strategies, that are not supported by Devise, or
  # change the failure app, you can configure them inside the config.warden block.
  #
  # config.warden do |manager|
  #   manager.failure_app   = AnotherApp
  #   manager.intercept_401 = false
  #   manager.default_strategies(:scope => :user).unshift :some_external_strategy
  # end
end

Gemfile

source 'http://rubygems.org'
gem 'rails', '3.1.0.rc4'
gem 'sass-rails', "~> 3.1.0.rc"
gem 'coffee-script'
gem 'uglifier'
gem "therubyracer", ">= 0.8.2"
gem "bson_ext", ">= 1.3.1"
gem "mongoid", ">= 2.0.2"
gem "rspec-rails", ">= 2.6.1", :group => [:development, :test]
gem "database_cleaner", ">= 0.6.7", :group => :test
gem "mongoid-rspec", ">= 1.4.4", :group => :test
gem "factory_girl_rails", ">= 1.1.rc1", :group => :test
gem "spork", "~> 0.9.0.rc", :group => :test
gem "autotest", "~> 4.4.6", :group => :test
gem "autotest-rails-pure", "~> 4.1.2", :group => :test
gem "autotest-fsevent", :group => :test
gem "autotest-growl", :group => :test
gem "haml", ">= 3.1.2"
gem "haml-rails", ">= 0.3.4", :group => :development
gem "devise", ">= 1.4.2"
gem "cucumber-rails", ">= 1.0.2", :group => :test
gem "capybara", ">= 1.0.0", :group => :test
gem "launchy", ">= 0.4.0", :group => :test
gem "ruby-debug19", :group => :development, :require => 'ruby-debug'

Gemfile.lock

GEM
  remote: http://rubygems.org/
  specs:
    ZenTest (4.5.0)
    actionmailer (3.1.0.rc4)
      actionpack (= 3.1.0.rc4)
      mail (~> 2.3.0)
    actionpack (3.1.0.rc4)
      activemodel (= 3.1.0.rc4)
      activesupport (= 3.1.0.rc4)
      builder (~> 3.0.0)
      erubis (~> 2.7.0)
      i18n (~> 0.6)
      rack (~> 1.3.0)
      rack-cache (~> 1.0.1)
      rack-mount (~> 0.8.1)
      rack-test (~> 0.6.0)
      sprockets (~> 2.0.0.beta.10)
      tzinfo (~> 0.3.27)
    activemodel (3.1.0.rc4)
      activesupport (= 3.1.0.rc4)
      bcrypt-ruby (~> 2.1.4)
      builder (~> 3.0.0)
      i18n (~> 0.6)
    activerecord (3.1.0.rc4)
      activemodel (= 3.1.0.rc4)
      activesupport (= 3.1.0.rc4)
      arel (~> 2.1.1)
      tzinfo (~> 0.3.27)
    activeresource (3.1.0.rc4)
      activemodel (= 3.1.0.rc4)
      activesupport (= 3.1.0.rc4)
    activesupport (3.1.0.rc4)
      multi_json (~> 1.0)
    archive-tar-minitar (0.5.2)
    arel (2.1.3)
    autotest (4.4.6)
      ZenTest (>= 4.4.1)
    autotest-fsevent (0.2.5)
      sys-uname
    autotest-growl (0.2.9)
    autotest-rails-pure (4.1.2)
    bcrypt-ruby (2.1.4)
    bson (1.3.1)
    bson_ext (1.3.1)
    builder (3.0.0)
    capybara (1.0.0)
      mime-types (>= 1.16)
      nokogiri (>= 1.3.3)
      rack (>= 1.0.0)
      rack-test (>= 0.5.4)
      selenium-webdriver (~> 0.2.0)
      xpath (~> 0.1.4)
    childprocess (0.1.9)
      ffi (~> 1.0.6)
    coffee-script (2.2.0)
      coffee-script-source
      execjs
    coffee-script-source (1.1.1)
    columnize (0.3.4)
    configuration (1.3.1)
    cucumber (1.0.1)
      builder (>= 2.1.2)
      diff-lcs (>= 1.1.2)
      gherkin (~> 2.4.5)
      json (>= 1.4.6)
      term-ansicolor (>= 1.0.5)
    cucumber-rails (1.0.2)
      capybara (>= 1.0.0)
      cucumber (~> 1.0.0)
      nokogiri (>= 1.4.6)
    database_cleaner (0.6.7)
    devise (1.4.2)
      bcrypt-ruby (~> 2.1.2)
      orm_adapter (~> 0.0.3)
      warden (~> 1.0.3)
    diff-lcs (1.1.2)
    erubis (2.7.0)
    execjs (1.2.0)
      multi_json (~> 1.0)
    factory_girl (2.0.0.rc4)
    factory_girl_rails (1.1.rc1)
      factory_girl (~> 2.0.0.rc)
      railties (>= 3.0.0)
    ffi (1.0.9)
    gherkin (2.4.5)
      json (>= 1.4.6)
    haml (3.1.2)
    haml-rails (0.3.4)
      actionpack (~> 3.0)
      activesupport (~> 3.0)
      haml (~> 3.0)
      railties (~> 3.0)
    hike (1.1.0)
    i18n (0.6.0)
    json (1.5.3)
    json_pure (1.5.3)
    launchy (0.4.0)
      configuration (>= 0.0.5)
      rake (>= 0.8.1)
    libv8 (3.3.10.2)
    linecache19 (0.5.12)
      ruby_core_source (>= 0.1.4)
    mail (2.3.0)
      i18n (>= 0.4.0)
      mime-types (~> 1.16)
      treetop (~> 1.4.8)
    mime-types (1.16)
    mongo (1.3.1)
      bson (>= 1.3.1)
    mongoid (2.0.2)
      activemodel (~> 3.0)
      mongo (~> 1.3)
      tzinfo (~> 0.3.22)
    mongoid-rspec (1.4.4)
      mongoid (~> 2.0)
      rspec (~> 2)
    multi_json (1.0.3)
    nokogiri (1.5.0)
    orm_adapter (0.0.5)
    polyglot (0.3.1)
    rack (1.3.1)
    rack-cache (1.0.2)
      rack (>= 0.4)
    rack-mount (0.8.1)
      rack (>= 1.0.0)
    rack-ssl (1.3.2)
      rack
    rack-test (0.6.0)
      rack (>= 1.0)
    rails (3.1.0.rc4)
      actionmailer (= 3.1.0.rc4)
      actionpack (= 3.1.0.rc4)
      activerecord (= 3.1.0.rc4)
      activeresource (= 3.1.0.rc4)
      activesupport (= 3.1.0.rc4)
      bundler (~> 1.0)
      railties (= 3.1.0.rc4)
    railties (3.1.0.rc4)
      actionpack (= 3.1.0.rc4)
      activesupport (= 3.1.0.rc4)
      rack-ssl (~> 1.3.2)
      rake (>= 0.8.7)
      rdoc (~> 3.4)
      thor (~> 0.14.6)
    rake (0.9.2)
    rdoc (3.8)
    rspec (2.6.0)
      rspec-core (~> 2.6.0)
      rspec-expectations (~> 2.6.0)
      rspec-mocks (~> 2.6.0)
    rspec-core (2.6.4)
    rspec-expectations (2.6.0)
      diff-lcs (~> 1.1.2)
    rspec-mocks (2.6.0)
    rspec-rails (2.6.1)
      actionpack (~> 3.0)
      activesupport (~> 3.0)
      railties (~> 3.0)
      rspec (~> 2.6.0)
    ruby-debug-base19 (0.11.25)
      columnize (>= 0.3.1)
      linecache19 (>= 0.5.11)
      ruby_core_source (>= 0.1.4)
    ruby-debug19 (0.11.6)
      columnize (>= 0.3.1)
      linecache19 (>= 0.5.11)
      ruby-debug-base19 (>= 0.11.19)
    ruby_core_source (0.1.5)
      archive-tar-minitar (>= 0.5.2)
    rubyzip (0.9.4)
    sass (3.1.4)
    sass-rails (3.1.0.rc.4)
      actionpack (~> 3.1.0.rc1)
      railties (~> 3.1.0.rc1)
      sass (>= 3.1.4)
      sprockets (>= 2.0.0.beta.9)
    selenium-webdriver (0.2.2)
      childprocess (>= 0.1.9)
      ffi (>= 1.0.7)
      json_pure
      rubyzip
    spork (0.9.0.rc9)
    sprockets (2.0.0.beta.10)
      hike (~> 1.0)
      rack (~> 1.0)
      tilt (!= 1.3.0, ~> 1.1)
    sys-uname (0.8.5)
    term-ansicolor (1.0.5)
    therubyracer (0.9.2)
      libv8 (~> 3.3.10)
    thor (0.14.6)
    tilt (1.3.2)
    treetop (1.4.9)
      polyglot (>= 0.3.1)
    tzinfo (0.3.29)
    uglifier (1.0.0)
      execjs (>= 0.3.0)
      multi_json (>= 1.0.2)
    warden (1.0.4)
      rack (>= 1.0)
    xpath (0.1.4)
      nokogiri (~> 1.3)

PLATFORMS
  ruby

DEPENDENCIES
  autotest (~> 4.4.6)
  autotest-fsevent
  autotest-growl
  autotest-rails-pure (~> 4.1.2)
  bson_ext (>= 1.3.1)
  capybara (>= 1.0.0)
  coffee-script
  cucumber-rails (>= 1.0.2)
  database_cleaner (>= 0.6.7)
  devise (>= 1.4.2)
  factory_girl_rails (>= 1.1.rc1)
  haml (>= 3.1.2)
  haml-rails (>= 0.3.4)
  launchy (>= 0.4.0)
  mongoid (>= 2.0.2)
  mongoid-rspec (>= 1.4.4)
  rails (= 3.1.0.rc4)
  rspec-rails (>= 2.6.1)
  ruby-debug19
  sass-rails (~> 3.1.0.rc)
  spork (~> 0.9.0.rc)
  therubyracer (>= 0.8.2)
  uglifier

user.rb

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

  field :name
  validates_presence_of :name
  validates_presence_of :email
  validates_uniqueness_of :name, :case_sensitive => false
  attr_accessible :name, :email, :password, :password_confirmation, :remember_me
end