development:
  adapter: sqlite3
  database: db/development.sqlite3
  timeout: 5000

test:
  adapter: sqlite3
  database: db/test.sqlite3
  timeout: 5000

production:
  adapter: sqlite3
  database: db/production.sqlite3
  timeout: 5000

config.assets.enabled

config.assets.enabled = false

config/application.rb
module モジュール名
  class Application < Rails::Application
    config.変数名 = 値

module Mysite
  class Application < Rails::Application
    config.title = "サイトの名前"

Mysite::Application.config.title

config.after_initialize do
  処理の内容
end

config.after_initialize do
  ActionView::Base.sanitized_allowed_tags.delete 'div'
end

config.asset_host = "ホスト名"

config.asset_host = "http://railsdoc.com/"

config.autoload_once_paths += %W(#{config.root}/ディレクトリ名)]

config.autoload_once_paths += %W(#{config.root}/lib)

config.cache_classes = true

config.cache_classes = false

config.action_view.cache_template_loading

config.action_view.cache_template_loading = true

config.consider_all_requests_local = ( true | false )

config.consider_all_requests_local = true

console do
  config.console = クラス名
end

console do
  require "pry"
  config.console = Pry
end

config.eager_load

config.eager_load = true

config.eager_load_namespaces

config.eager_load_namespaces << SimpleForm

config.eager_load_paths

config.eager_load_paths += %W( #{RAILS_ROOT}/app/workers )

config.encoding = 文字コード

config.encoding = euc-jp

config.exceptions_app

config.exceptions_app = self.routes

config.file_watcher

config.file_watcher = ActiveSupport::EventedFileUpdateChecker

config.filter_parameters += [パラメータ]

config.filter_parameters += [:password]

config.force_ssl

config.force_ssl = true

config.log_level = ( :debug | :info | :warn | :error | :fatal )

config.log_level = :info

config.log_tags

config.log_tags = [:uuid, :remote_ip]

config.logger = Logger.new(ログのパス, 条件)

config.logger = Logger.new(config.log_path, 'daily')

config.logger = Logger.new(config.log_path, 10, 10.megabytes)

config.logger =nil

config.reload_classes_only_on_change

config.reload_classes_only_on_change = false

config.secret_key_base

config.secret_key_base = 'myapp1234'

config.colorize_logging

config.active_record.colorize_logging = false

config.session_store

config.session_store :cookie_store, key: '_your_app_session'

config.time_zone = 'タイムゾーンの設定'

config.time_zone = 'Tokyo'

$ rake time:zones:all

$ rake time:zones:local

config.beginning_of_week = :曜日

config.beginning_of_week = :monday

config.assets.css_compressor

config.assets.css_compressor = :yui

config.assets.js_compressor

config.assets.js_compressor = :uglifier

config.assets.paths

config.assets.paths << Rails.root.join("app", "assets", "flash")

config.assets.precompile

config.assets.precompile += ['admin.js', 'admin.css', 'swfObject.js']

config.assets.prefix

config.assets.prefix = "/some_other_path"

config.assets.digest

config.assets.digest = true

config.assets.debug

config.assets.debug = true

config.autoload_paths += %W(#{config.root}/ディレクトリ名)

config.autoload_paths += %W(#{config.root}/lib)

config.cache_store

config.cache_store = [ :file_store, "/tmp/rails-cache/assets/#{Rails.env}/" ]

config.assets.version = バージョン

config.assets.version = '1.0'

config.assets.compile = Bool値

config.assets.compile = true

config.assets.logger

config.assets.logger = false

config.middleware

config.middleware.use

config.middleware.use JQuery::FileUpload::Rails::Middleware

config.middleware.swap

config.middleware.swap ActionController::Failsafe, Lifo::Failsafe

config.middleware.delete

config.middleware.delete Sass::Plugin::Rack

config.middleware.insert_after

config.middleware.insert_after Rack::MethodOverride

config.i18n.default_locale = 国コード

config.i18n.default_locale = :ja

config.i18n.load_path

config.i18n.load_path += Dir[Rails.root.join('config/locales/**/*.yml').to_s]

config.active_record.logger = logger

config.active_record.logger = Logger.new("log/development_sql.log")

config.active_record.primary_key_prefix_type = 主キー名

config.active_record.primary_key_prefix_type = :table_name_with_underscore

config.active_record.table_name_prefix = "prefix"

config.active_record.table_name_prefix = "northwest_"

config.active_record.table_name_suffix = suffix

config.active_record.table_name_suffix = "_northwest"

config.active_record.pluralize_table_names

config.active_record.pluralize_table_names = false

config.active_record.default_timezone = ( :local | :utc )

config.active_record.default_timezone = :utc

config.active_record.schema_format = 形式

config.active_record.schema_format = :sql

config.active_record.timestamped_migrations = Bool値

config.active_record.timestamped_migrations = false

config.active_record.lock_optimistically = Bool値

config.active_record.lock_optimistically = false

config.action_controller.asset_host = URL

config.action_controller.asset_host = "http://railsdoc.com"

config.action_controller.perform_caching = Bool値

config.action_controller.perform_caching = true

config.action_controller.default_static_extension = 拡張子

config.action_controller.default_static_extension = '.php'

config.action_controller.default_charset = 文字コード

config.action_controller.default_charset = "euc-jp"

config.action_controller.request_forgery_protection_token

config.action_controller.request_forgery_protection_token = '_xsrf_token_here'

config.action_controller.allow_forgery_protection = Bool値

config.action_controller.allow_forgery_protection = true

config.action_controller.relative_url_root

config.action_controller.relative_url_root = "/myapp"

config.action_controller.permit_all_parameters = Bool値

config.action_controller.permit_all_parameters = true

config.action_controller.logger

config.action_controller.logger = Log4r

config.action_controller.action_on_unpermitted_parameters

config.action_controller.action_on_unpermitted_parameters = :raise

Proc.new do |html_tag, instance|
  %Q(<div class="field_with_errors">#{html_tag}</div>).html_safe
end

config.action_view.field_error_proc

config.action_view.field_error_proc = Proc.new { |html_tag, instance|
  "#{html_tag}".html_safe
}

config.action_view.default_form_builder

config.action_view.default_form_builder = "ApplicationHelper::TestFormBuilder"

config.action_view.erb_trim_mode = "区切り文字"

config.action_view.erb_trim_mode = -"

config.action_view.embed_authenticity_token_in_remote_forms = Bool値

config.action_view.embed_authenticity_token_in_remote_forms = false

config.action_view.prefix_partial_path_with_controller_namespace = Bool値

config.action_view.prefix_partial_path_with_controller_namespace = false

config.action_view.logger = ロガー名

config.action_view.logger = Log4r

config.action_view.logger = nil

config.action_mailer.logger

config.action_mailer.logger = ActiveSupport::BufferedLogger.new("mailer.log")

config.action_mailer.smtp_settings

config.action_mailer.smtp_settings = {
  address:        'railsdoc.com',
  domain:         'railsdoc.com',
  port:           80,
  user_name:      'example@example.com',
  password:       'yourpassword',
  authentication: :plain
}

config.action_mailer.sendmail_settings = オプション

config.action_mailer.sendmail_settings = {
  location:  '/usr/sbin/sendmail',
  arguments: '-i -t'
}

config.action_mailer.raise_delivery_errors = Bool値

config.action_mailer.raise_delivery_errors = false

config.action_mailer.delivery_method = ( :smtp | :sendmail | :test )

config.action_mailer.delivery_method = :sendmail

config.action_mailer.perform_deliveries = Bool値

config.action_mailer.perform_deliveries = false

config.action_mailer.default_options = デフォルトのオプション

config.action_mailer.default_options = {
  from: "example@example.com"
}

config.action_mailer.observers = オブザーバー

config.action_mailer.observers = ["MailObserver"]

config.action_mailer.interceptors = インタープリタ

config.action_mailer.interceptors = ["MailInterceptor"]

config.action_dispatch.session_store = セッションストア名

config.action_dispatch.session_store = :active_record_store

config.action_dispatch.default_headers = {
  X-Frame-Options: 'SAMEORIGIN',
  X-XSS-Protection: '1; mode=block',
  X-Content-Type-Options: 'nosniff'
}

config.action_dispatch.default_headers

config.action_dispatch.default_headers = {
  X-Frame-Options: 'DENY',
  X-XSS-Protection: '0',
  X-Content-Type-Options: 'nosniff',
  X-UA-Compatible: 'IE=EmulateIE7'
}

config.action_dispatch.tld_length = 数値

config.action_dispatch.tld_length = 2

ActionDispatch::Callbacks.to_prepare = ( true | false )

ActionDispatch::Callbacks.to_prepare = true

ActionDispatch::Callbacks.after

ActionDispatch::Callbacks.after do
  load 'filename_in_lib'
  # or
  Dir.entries("#{Rails.root}/lib").each do |entry|
    load entry if entry =~ /.rb$/
  end
end

config.active_support.bare = Bool値

config.active_support.bare = true

config.active_support.escape_html_entities_in_json = Bool値

config.active_support.escape_html_entities_in_json = true

config.active_support.use_standard_json_time_format = Bool値

config.active_support.use_standard_json_time_format = false

ActiveSupport::Cache::Store.logger

ActiveSupport::Cache::Store.logger = Logger.new(STDOUT)

ActiveSupport::Deprecation.behavior

ActiveSupport::Deprecation.behavior = :notify

ActiveSupport::Deprecation.silence

ActiveSupport::Deprecation.silence { extend ActiveSupport::Memoizable }

ActiveSupport::Deprecation.silenced

ActiveSupport::Deprecation.silenced = true

ActiveSupport::Logger.silencer

ActiveSupport::Logger.silencer = false

after_validation(メソッド名 [, ...])

after_validation :set_status

before_validation(引数 [, ...])

before_validation :remove_whitespaces
private
def remove_whitespaces
  name.strip!
end

config.disable_sandbox = Bool値

config.disable_sandbox = true

config.enable_dependency_loading

config.enable_dependency_loading = true

config.debug_exception_response_format

config.debug_exception_response_format = :api

config.log_formatter

config.log_formatter = Logger::Formatter.new

config.credentials.content_path

config.credentials.key_path