Mongoid Genesis
===============

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Mongoid Genesis will give you the ability to override data in your model
without losing the initial data.

Install
-------

```
gem install mongoid-genesis
```

Rails 3
-------

In your Gemfile:

```ruby
gem 'mongoid-genesis'
```

Usage
-----

Mongoid Genesis is compatible with any mongoid collection or embedded object.


#### Model integration

```ruby
class Book
  include Mongoid::Document
  include Mongoid::Genesis
end
```

This will create an embedded object that will store the original data.

#### Basic structure

```ruby
book = Book.new(:title => 'The Art of War', :author => 'Sun Tzu')
#=> #<Book _id: 1, title: "The Art of War", author: "Sun Tzu">

book.genesis
#=> #<BookGenesis _id: 1>
```

#### Preserve the original attribute

```ruby
book.write_and_preserve_attribute(:author, 'Sun Zi')
#=> #<Book _id: 1, title: "The Art of War", author: "Sun Zi">

book.genesis
#=> #<BookGenesis _id: 1, author: "Sun Tzu">
```

#### After preserving the original attribute, it will not be overwritten

```ruby
book.write_and_preserve_attribute(:author, 'Sun Wu')
#=> #<Book _id: 1, title: "The Art of War", author: "Sun Wu">

book.genesis
#=> #<BookGenesis _id: 1, author: "Sun Tzu">
```

#### At all time, you can read the original attribute

```ruby
book.read_attribute_genesis(:title)
#=> "The Art of War"

book.write_and_preserve_attribute(:title, 'The Art of Peace')
book.read_attribute_genesis(:title)
#=> "The Art of War"
```

#### You can restore the original attribute

```ruby
book.restore_genesis(:author)
#=> #<Book _id: 1, title: "The Art of War", author: "Sun Tzu">

book.genesis
#=> #<BookGenesis _id: 1, author: nil>
```

#### To update the original document without losing the current state

```ruby
book.write_and_preserve_attribute(:title, 'The Art of Peace')
book.reverse_genesis

#=> #<Book _id: 1, title: "The Art of War", author: "Sun Tzu">
#=> #<BookGenesis _id: 1, title: "The Art of Peace">

book.title = "The Art of War : Revisited"
book.reverse_genesis

#=> #<Book _id: 1, title: "The Art of Peace", author: "Sun Tzu">
#=> #<BookGenesis _id: 1, title: "The Art of War : Revisited">
```

Cheat Sheet
---------

#### read_attribute_genesis(field_name)
Read the original attribute of the record. If the attribute wasn't overwritten, it will return the same thing as .read_attribute.

#### restore_genesis(field_name)
Restore the original value for the given field


#### reverse_genesis
Restore the record to its original state


#### write_and_preserve_attribute(field_name, value)
Overwrite the attribute with the *value* and saves the original value in the genesis object.



Copyright
---------

Copyright (c) 2012 De Marque inc. See LICENSE for further details.