Deleting Mongodb lock file

cd /var/lib/mongodb
rm -rf mongodb.lock

Configuring mongo id for rails

Add the following gems to your Gem file of your rails app

gem 'mongoid', github: 'mongoid/mongoid'
gem 'bson'
# gem 'bson_ext', '~> 1.9.2'

make bundle install

rails g mongoid:config

First in config/application.rb comment out the line and add the following to enable mongodb

# require 'rails/all'
require "action_controller/railtie"
require "action_mailer/railtie"
# require "active_resource/railtie"

require "sprockets/railtie"

In config/environments/development.rb, comment out this line
# config.active_record.migration_error = :page_load

Let’s generate our Post first, it will have 3 fields: a title, a body and it can be starred.
rails g scaffold post title:string body:string starred:boolean

Add fields to your model
class Post
  include Mongoid::Document
  include Mongoid::Timestamps

  field :title, type: String
  field :body, type: String
  field :starred, type: Boolean

  index({ starred: 1 })

end

Now we have a command to enforce indexes on the database
rake db:mongoid:create_indexes

if you've the database connection error, try doing the following two things 
uncomment 127.0.0.1 host line in C:\Windows\System32\drivers\etc\hosts
or
in mongoid.yml file, change the hosts to the following
hosts:

        - 127.0.0.1:27017

Read more at
http://requiremind.com/riding-rails-4-along-with-mongoid-and-ruby-2-dot-0/

Adding devise on Mongoid

Configure ActionMailer

Set up action_mailer in your development environment in the file

config/environments/development.rb

by commenting out the line in the file:

# Don't care if the mailer can't send

# config.action_mailer.raise_delivery_errors = false

and adding:

# ActionMailer Config

config.action_mailer.default_url_options = { :host => 'localhost:3000' }

# A dummy setup for development - no deliveries, but logged

config.action_mailer.delivery_method = :smtp

config.action_mailer.perform_deliveries = false

config.action_mailer.raise_delivery_errors = true

config.action_mailer.default :charset => "utf-8"

Set up action_mailer in your production environment in the file

config/environments/production.rb

by adding:

config.action_mailer.default_url_options = { :host => 'yourhost.com' }

# ActionMailer Config

# Setup for production - deliveries, no errors raised

config.action_mailer.delivery_method = :smtp

config.action_mailer.perform_deliveries = true

config.action_mailer.raise_delivery_errors = false

config.action_mailer.default :charset => "utf-8"

Installing devise

$ rails generate devise:install

which installs a configuration file:

config/initializers/devise.rb

and a localization file.

Devise will recognize that you already have Mongoid installed and it will set its ORM configuration in the config/initializers/devise.rb file to include:

require 'devise/orm/mongoid'

Adding devise users

Generate a Model and Routes for Users

Devise can manage users and administrators separately, allowing two (or more) roles to be implemented differently. For this example, we just implement Users.

Use Devise to generate models and routes for a User:

$ rails generate devise User

Devise will recognize that Mongoid is installed and set up the User model with

include Mongoid::Document

which must precede all other statements in the model.

Devise will modify the config/routes.rb file to add:

devise_for :users

Add these manually in developer.rb model class to generate routes

  # traditional devise need to manually place in mongodb generated devise
  devise :database_authenticatable, :registerable,

         :recoverable, :rememberable, :trackable, :validatable

Modify the file models/user.rb and add:

field :name

validates_presence_of :name

validates_uniqueness_of :name, :email, :case_sensitive => false

attr_accessible :name, :email, :password, :password_confirmation, :remember_me

rails g devise:views to add view files

Set Up a Demonstration of Devise

$ rails generate controller users show

Note that “users” is plural when you create the controller.

Modify the file app/controllers/users_controller.rb and add:

before_filter :authenticate_user!

def show

  @user = User.find(params[:id])

end

The file config/routes.rb has already been modified to include:

get "users/show"

Remove that and change the routes to:

root :to => "home#index"

devise_for :users

resources :users

Important note: The devise_for :users route must be placed above resources :users.

This line needs to be commented out in config/nitialiser/cookies_serialiser.rb or you will get cookies errors while logging in

# Rails.application.config.action_dispatch.cookies_serializer = :json

Comment out the following line to stop conflict with previous active records

# Do not dump schema after migrations.

  # config.active_record.dump_schema_after_migration = false

Add production config in config/mongoid.yml file

production:
  # Configure available database sessions. (required)
  sessions:
    # Defines the default session. (required)
    default:
      database: analytics_server_rails_production
      # Provides the hosts the default session can connect to. Must be an array
      # of host:port pairs. (required)
      hosts:
        - 127.0.0.1:27017
      options:
        # Change the default write concern. (default = { w: 1 })
        # write:
        # w: 1

        # Change the default consistency model to primary, secondary.
        # 'secondary' will send reads to secondaries, 'primary' sends everything
        # to master. (default: primary)
        # read: secondary_preferred

        # How many times Moped should attempt to retry an operation after
        # failure. (default: The number of nodes in the cluster)
        # max_retries: 20

        # The time in seconds that Moped should wait before retrying an
        # operation on failure. (default: 0.25)
        # retry_interval: 0.25
  # Configure Mongoid specific options. (optional)

  options: