Railsmdb is a command-line utility for creating, updating, managing, and maintaining Rails applications that use Mongoid and MongoDB for data storage. It is an extension of (and supports all other functionality of) the rails command from Ruby on Rails.

To install Railsmdb:

$ gem install railsmdb

This will install a new command, railsmdb.

The railsmdb command may be invoked exactly as you would invoke the rails command. For example, to create a new Rails app:

$ railsmdb new my_new_rails_app

This will create a new folder under the current directory called my_new_rails_app, and will populate it with all the scaffolding necessary to begin building your app.

Unlike the rails command, however, it will set up the necessary gems and configuration for you to begin your Rails app using the MongoDB database, with Mongoid as the Object-Document Mapper (ODM).

Also, in your new application, there will be a new script in the bin folder: bin/railsmdb. You'll see bin/rails in there as well, but it now links to bin/railsmdb.

By default, railsmdb will not include ActiveRecord in your new application. If you wish to use both Mongoid and ActiveRecord (to connect to MongoDB and a separate, relational database in the same application), you can pass --no-skip-active-record:

$ railsmdb new my_new_rails_app --no-skip-active-record

This will set up your application to use both Mongoid, and sqlite3 (by default). To start with a different relational database instead, you can pass the --database option:

$ railsmdb new my_new_rails_app --no-skip-active-record --database=mysql

To see a list of all available commands, simply type railsmdb without any arguments.

$ railsmdb

# alternatively:
$ railsmdb -h

If you want to add railsmdb to an existing (non-Mongoid) Rails app, and add Mongoid configuration as well, you can use railsmdb setup:

$ railsmdb setup

This must be run from the root directory of a Rails project. It will replace bin/rails with bin/railsmdb, add the mongoid.yml configuration file and the mongoid.rb initializer, and add the necessary gem entries to the Gemfile.

Note: it is recommended to run this command in a branch, so that you can easily experiment with the changes and roll them back if necessary.

You can use railsmdb to generate stubs for new Mongoid models. From within a project:

$ bin/railsmdb generate model person

This will create a new model at app/models/person.rb:

class Person
  include Mongoid::Document
  include Mongoid::Timestamp
end

You can specify the fields of the model as well:

# bin/railsmdb generate model person name:string birth:date

class Person
  include Mongoid::Document
  include Mongoid::Timestamp
  field :name, type: String
  field :birth, type: Date
end

You can instruct the generator to make the new model a subclass of another, by passing the --parent option:

# bin/railsmdb generate model student --parent=person

class Student < Person
  include Mongoid::Timestamp
end

And if you need to store your models in a different collection than can be inferred from the model name, you can specify --collection:

# bin/railsmdb generate model course --collection=classes

class Course
  include Mongoid::Document
  include Mongoid::Timestamp
  store_in collection: 'classes'
end