我的 mongoid.yml：
production:
sessions:
default:
database: kvallspressen_production
hosts:
- localhost:27017
options:
options:
development:
# 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: kvallspressen_development
# 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:
# Configuration for whether or not to allow access to fields that do
# not have a field definition on the model. (default: true)
# allow_dynamic_fields: true
# Enable the identity map, needed for eager loading. (default: false)
# identity_map_enabled: false
# Includes the root model name in json serialization. (default: false)
# include_root_in_json: false
# Include the _type field in serializaion. (default: false)
# include_type_for_serialization: false
# Preload all models in development, needed when models use
# inheritance. (default: false)
# preload_models: false
# Protect id and type from mass assignment. (default: true)
# protect_sensitive_fields: true
# Raise an error when performing a #find and the document is not found.
# (default: true)
# raise_not_found_error: true
# Raise an error when defining a scope with the same name as an
# existing method. (default: false)
# scope_overwrite_exception: false
# Skip the database version check, used when connecting to a db without
# admin access. (default: false)
# skip_version_check: false
# User Active Support's time zone in conversions. (default: true)
# use_activesupport_time_zone: true
# Ensure all times are UTC in the app side. (default: false)
# use_utc: false
test:
sessions:
default:
database: kvallspressen_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
当我跑RAILS_ENV=production rake db:create
我收到此错误：
** Invoke db:create (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
undefined method `has_key?' for nil:NilClass
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config/validators/session.rb:99:in `no_database_or_uri?'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config/validators/session.rb:45:in `validate_session_database'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config/validators/session.rb:25:in `block in validate'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config/validators/session.rb:24:in `each_pair'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config/validators/session.rb:24:in `validate'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config.rb:183:in `sessions='
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config.rb:213:in `load_configuration'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/config.rb:85:in `load!'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid.rb:146:in `load!'
/usr/local/lib/ruby/gems/2.0.0/gems/mongoid-3.0.23/lib/mongoid/railtie.rb:67:in `block in <class:Railtie>'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/initializable.rb:30:in `instance_exec'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/initializable.rb:30:in `run'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/initializable.rb:55:in `block in run_initializers'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/initializable.rb:54:in `each'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/initializable.rb:54:in `run_initializers'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/application.rb:136:in `initialize!'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/railtie/configurable.rb:30:in `method_missing'
/var/www/kvallspressen/config/environment.rb:5:in `<top (required)>'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/application.rb:103:in `require'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/application.rb:103:in `require_environment!'
/usr/local/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/application.rb:297:in `block (2 levels) in initialize_tasks'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:228:in `call'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:228:in `block in execute'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:223:in `each'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:223:in `execute'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:166:in `block in invoke_with_call_chain'
/usr/local/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:159:in `invoke_with_call_chain'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:187:in `block in invoke_prerequisites'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:185:in `each'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:185:in `invoke_prerequisites'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:165:in `block in invoke_with_call_chain'
/usr/local/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:159:in `invoke_with_call_chain'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/task.rb:152:in `invoke'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:143:in `invoke_task'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:101:in `each'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:101:in `block in top_level'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:110:in `run_with_threads'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:95:in `top_level'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:73:in `block in run'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:160:in `standard_exception_handling'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/lib/rake/application.rb:70:in `run'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.0.3/bin/rake:33:in `<top (required)>'
/usr/local/bin/rake:23:in `load'
/usr/local/bin/rake:23:in `<main>'
Tasks: TOP => db:create => environment
宝石文件：
source 'http://rubygems.org'
gem 'rails', '3.2.12'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'
# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem "less-rails", "~> 2.2.6"
gem 'coffee-rails', '~> 3.2.1'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
gem 'therubyracer', :platforms => :ruby
gem "sass-rails", "~> 3.2.6"
gem "twitter-bootstrap-rails", '2.1.4'
gem 'bootstrap-sass', '~> 2.3.0.1'
gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# To use Jbuilder templates for JSON
# gem 'jbuilder'
# Use unicorn as the app server
gem 'unicorn'
# Deploy with Capistrano
# gem 'capistrano'
# To use debugger
# gem 'debugger'
gem "mongoid", "~> 3.0.0"
我在 Ubuntu 10.04.4 LTS 上，使用 rails 3.2.12，ruby 2.0.0p0（2013-02-24 修订版 39474）[i686-linux]
刚刚在我的本地环境中进行了测试。OSX 10.8.x 并出现相同的错误。
我错过了什么？