= RoleModel

Ever needed to assign roles to a model, say a User, and build conditional
behaviour on top of that?

Assigned roles will be stored as a bitmask in an configurable attribute
(default: <tt>roles_mask</tt>). Here's how to get started:

  # given a User class with a roles_mask attribute
  require 'rubygems'
  require 'role_model'

  class User
    attr_accessor :roles_mask # in real life this would be an persisted attribute / DB-column
    
    include RoleModel

    # optionally set the integer attribute to store the roles in,
    # :roles_mask is the default
    roles_attribute :roles_mask
    
    # declare the valid roles -- do not change the order if you add more
    # roles later, always append them at the end!
    roles :admin, :manager, :author
  end
  
  #
  # Test drive
  #

  >> u = User.new
  => #<User ...>

  # role assignment
  >> u.roles = [:admin]  # ['admin'] works as well
  => [:admin]

  # adding roles
  >> u.roles << :manager
  => [:admin, :manager]
  
  # quering roles...

  # ... retrieve all assigned roles
  >> u.roles # aliased to role_symbols for DeclarativeAuthorization
  => [:admin, :manager]

  # ... check for individual roles
  >> u.has_role? :author
  => false
  >> u.is_a? :admin  # has_role? is aliased as is_a?
  => true

  # see the internal bitmask representation (3 = 0b0011)
  >> u.roles_mask
  => 3

Once you have included RoleModel, your model is perfectly fit to be used
together with a role-based authorization solution, such as
http://github.com/ryanb/cancan or
http://github.com/stffn/declarative_authorization .

== Installation

  gem install role_model

== Reasoning

Whenever I introduce a role-based authorization scheme into a project, the
code gets coupled somehow to the available roles. So it usually does not make
any sense to have a separate Role model stored within the database. This Role
model will contain a predefined set of roles anyhow -- changing that set will
need to be reflected within the authorization code. Putting the available
roles right into the model that actually uses them, makes things much easier
and efficient.

== Note on Patches/Pull Requests

* Fork the project.
* Make your feature addition or bug fix.
* Add tests for it. This is important so I don't break it in a
  future version unintentionally.
* Commit, do not mess with Rakefile, version, or history.
  (if you want to have your own version, that is fine but bump version in a
  commit by itself I can ignore when I pull)
* Send me a pull request. Bonus points for topic branches.

== Credits

RoleModel is an implementation of the Role Based Authorization scheme
proposed by Ryan Bates
(http://wiki.github.com/ryanb/cancan/role-based-authorization).

== Copyright

Copyright (c) 2010 Martin Rehfeld. See LICENSE for details.