Rails4 Collection Check Boxes

Using

collection_check_boxes

API: http://edgeapi.rubyonrails.org/classes/ActionView/Helpers/FormBuilder.html#method-i-collection_check_boxes

Font: http://blog.remarkablelabs.com/2012/12/collection-form-helpers-rails-4-countdown-to-2013

Don't forget to add the permission on your controller, something like:

require(:post).permit(category_ids: [])