rails s gets error for devise configuration to send mail

config/initializers/devise.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 Devise::Mailer,
  # note that it will be overwritten if you use your own mailer class with default "from" parameter.
  config.mailer_sender = "abc@gmail.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/active_record'

  # ==> Configuration for any authentication mechanism
  # Configure which keys are used when authenticati开发者_运维问答ng 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.
  #
  # Limiting the stretches to just one in testing will increase the performance of
  # your test suite dramatically. However, it is STRONGLY RECOMMENDED to not use
  # a value less than 10 in other environments.
  config.stretches = Rails.env.test? ? 1 : 10

  # Setup a pepper to generate the encrypted password.
  # config.pepper = "b1179d3eccc2985aa7e9e438d8866464943f84449e53014c19852e795fdc4c17ca0b779e843ea8826589c213aff8c91c16c4a937685a183b622899e0dbf120a6"

  # ==> Configuration for :confirmable
  # A period that the user is allowed to access the website even without
  # confirming his account. For instance, if set to 2.days, the user will be
  # able to access the website for two days without confirming his account,
  # access will be blocked just in the third day. Default is 0.days, meaning
  # the user cannot access the website without confirming his account.
  # 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

  # Email regex used to validate email formats. It simply asserts that
  # an one (and only one) @ exists in the given string. This is mainly
  # to give user feedback and not to assert the e-mail validity.
  # config.email_regexp = /\A[^@]+@[^@]+\z/

  # ==> 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 = :delete

  # ==> 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

  config.action_mailer.delivery_method = :smtp

  config.action_mailer.smtp_settings = {
    :tls => true,
    :enable_starttls_auto => true,
    :address => "smtp.gmail.com",
    :port => "587",
    :domain => "gmail.com",
    :authentication => :plain,
    :user_name => "abc@gmail.com",
    :password => "abc"
    }

end

If i remove these=>

  config.action_mailer.delivery_method = :smtp

  config.action_mailer.smtp_settings = {
    :tls => true,
    :enable_starttls_auto => true,
    :address => "smtp.gmail.com",
    :port => "587",
    :domain => "gmail.com",
    :authentication => :plain,
    :user_name => "abc@gmail.com",
    :password => "abc"
    }

then there is no problem.

Otherwise if i do rails s i get error=>

=> Booting WEBrick
=> Rails 3.1.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/user1/rorblog/config/initializers/devise.rb:211:in `block in <top (required)>': undefined method `action_mailer' for Devise:Module (NoMethodError)
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/devise-1.4.8/lib/devise.rb:250:in `setup'
    from /home/user1/rorblog/config/initializers/devise.rb:3:in `<top (required)>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:234:in `load'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:234:in `block in load'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:223:in `block in load_dependency'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:640:in `new_constants_in'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:223:in `load_dependency'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:234:in `load'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/engine.rb:556:in `block (2 levels) in <class:Engine>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/engine.rb:555:in `each'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/engine.rb:555:in `block in <class:Engine>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/initializable.rb:30:in `instance_exec'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/initializable.rb:30:in `run'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/initializable.rb:55:in `block in run_initializers'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/initializable.rb:54:in `each'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/initializable.rb:54:in `run_initializers'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/application.rb:96:in `initialize!'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/railtie/configurable.rb:30:in `method_missing'
    from /home/user1/rorblog/config/environment.rb:5:in `<top (required)>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:240:in `require'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:240:in `block in require'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:223:in `block in load_dependency'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:640:in `new_constants_in'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:223:in `load_dependency'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.1/lib/active_support/dependencies.rb:240:in `require'
    from /home/user1/rorblog/config.ru:4:in `block in <main>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/builder.rb:51:in `instance_eval'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/builder.rb:51:in `initialize'
    from /home/user1/rorblog/config.ru:1:in `new'
    from /home/user1/rorblog/config.ru:1:in `<main>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/builder.rb:40:in `eval'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/builder.rb:40:in `parse_file'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/server.rb:200:in `app'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/commands/server.rb:46:in `app'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/server.rb:301:in `wrapped_app'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.3.3/lib/rack/server.rb:252:in `start'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/commands/server.rb:70:in `start'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/commands.rb:54:in `block in <top (required)>'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/commands.rb:49:in `tap'
    from /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.1/lib/rails/commands.rb:49:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

The config.action_mailer lines should go in the Rails configuration file for the environment you want that configuration used in. So for development use: app/config/environments/development.rb and production: app/config/environments/production.rb