# ActsAsJoinable

It extends the functionality of `has_and_belongs_to_many`, conventionalizing common use cases.

## Usage

### Install

    sudo gem install acts-as-joinable
    
### Add Relationships

Say you have `Post` and `Asset` models.  If each `has_many` of each other `through` some join model, you can write it as such:

    class Post < ActiveRecord::Base
      acts_as_joinable_on :assets, :layouts, :tags, :slugs
    end
    
    class Asset < ActiveRecord::Base
      acts_as_joinable
    end
    
That is a replacement for the longer (and non-polymorphic):

    class Post < ActiveRecord::Base
      has_and_belongs_to_many :assets
    end
    
    class Asset < ActiveRecord::Base
      has_and_belongs_to_many :posts
    end

## Why

Many-to-many relationships end up requiring the same features 99% of the time:

1. Join Table that keeps track of `context`
  - [ActsAsTaggableOn](http://github.com/mbleigh/acts-as-taggable-on/blob/master/lib/generators/acts_as_taggable_on/migration/templates/active_record/migration.rb)
  - ActsAsAuthorized
  - [Preferences](http://github.com/pluginaweek/preferences/blob/master/generators/preferences/templates/001_create_preferences.rb)
  - [FriendlyId](http://github.com/norman/friendly_id/blob/ca9821192c8c3c4e81a938603151645c7cbe1470/generators/friendly_id/templates/create_slugs.rb)

It looks like this:

    create_table :relationships do |t|
      t.references :parent, :polymorphic => true
      t.references :child, :polymorphic => true
      t.string :context
      t.timestamps
    end

## Alternatives

- [ActsAsRelationable](http://github.com/winton/acts_as_relationable)