Merge branch 'master' into develop
Added roles admin, validator, author and guest by default
Added CanCan and roles
Merge branch 'develop'

Conflicts:
	app/controllers/application_controller.rb
	app/controllers/articles_controller.rb
	app/controllers/documents_controller.rb
	app/models/user.rb
	app/views/layouts/_topnavbar.html.haml
	db/schema.rb