unable to run my rails application with mongodb - ruby-on-rails

Question

I am working on rails project where i have used mongodb as backend , i am using mongo_mapper as ORM , i have followed the instructions from the below site
: http://www.mongodb.org/display/DOCS/Rails+3+-+Getting+Started .
But while running the server (i.e rails s or rails c) i am getting the following error.
/home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/to_ruby.rb:196:in `merge!': can't convert String into Hash (TypeError)
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/to_ruby.rb:196:in `block in visit_Psych_Nodes_Mapping'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/to_ruby.rb:190:in `each'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/to_ruby.rb:190:in `each_slice'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/to_ruby.rb:190:in `visit_Psych_Nodes_Mapping'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/visitor.rb:7:in `accept'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/to_ruby.rb:16:in `accept'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/nodes/node.rb:25:in `to_ruby'
from /home/vijay/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych.rb:107:in `load'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/mongo_mapper-0.11.0/lib/mongo_mapper/railtie.rb:27:in `block in <class:Railtie>'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/initializable.rb:30:in `instance_exec'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/initializable.rb:30:in `run'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/initializable.rb:55:in `block in run_initializers'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/initializable.rb:54:in `each'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/initializable.rb:54:in `run_initializers'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/application.rb:96:in `initialize!'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /home/vijay/Desktop/rails_project/newfolder/Mongo_St/config/environment.rb:5:in `<top (required)>'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/application.rb:83:in `require'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/application.rb:83:in `require_environment!'
from /home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/rails/commands.rb:39:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
Here is my application.rb
require File.expand_path('../boot', __FILE__)
# Pick the frameworks you want:
# require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "sprockets/railtie"
require "rails/test_unit/railtie"
if defined?(Bundler)
# If you precompile assets before deploying to production, use this line
Bundler.require(*Rails.groups(:assets => %w(development test)))
# If you want your assets lazily compiled in production, use this line
# Bundler.require(:default, :assets, Rails.env)
end
module MongoSt
class Application < Rails::Application
# Settings in config/environments/* take precedence over those specified here.
# Application configuration should go into files in config/initializers
# -- all .rb files in that directory are automatically loaded.
# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)
# Only load the plugins named here, in the order given (default is alphabetical).
# :all can be used as a placeholder for all plugins not explicitly named.
# config.plugins = [ :exception_notification, :ssl_requirement, :all ]
# Activate observers that should always be running.
# config.active_record.observers = :cacher, :garbage_collector, :forum_observer
# Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
# Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
# config.time_zone = 'Central Time (US & Canada)'
# The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
# config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
# config.i18n.default_locale = :de
# Configure the default encoding used in templates for Ruby 1.9.
config.encoding = "utf-8"
# Configure sensitive parameters which will be filtered from the log file.
config.filter_parameters += [:password]
# Enable the asset pipeline
config.assets.enabled = true
# Version of your assets, change this if you want to expire all your assets
config.assets.version = '1.0'
end
end
Gemfile :
source 'http://rubygems.org'
gem 'rails', '3.1.1'
# 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 'sass-rails', '~> 3.1.4'
gem 'coffee-rails', '~> 3.1.1'
gem 'uglifier', '>= 1.0.3'
end
gem 'execjs'
gem 'therubyracer'
gem 'jquery-rails'
#mongo db drivers
gem "mongo_mapper"
gem "bson_ext"
gem 'jquery-rails'
# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# Use unicorn as the web server
# gem 'unicorn'
# Deploy with Capistrano
# gem 'capistrano'
# To use debugger
# gem 'ruby-debug19', :require => 'ruby-debug'
group :test do
# Pretty printed test output
gem 'turn', :require => false
end
I am new to this environment , so kindly help me in this or provide me any links which will be helpful.
Thanks

Answer 1

I have got the answer for it, Firstly i have created file called 'mongo.yml' in config folder , i have renamed file to 'mongodb.yml'. Its working fine. Basically this file contains details about the connection of database.
mongodb.yml file contain the following code
base: &base
adapter: mongodb
database: test
host: localhost
development:
<<: *base