collection_check_boxes doesn't work if all are unchecked.

[rjocoleman]

https://github.com/rails/rails/blob/4-0-stable/actionpack/lib/action_view/helpers/form_options_helper.rb#L674-L681

Rails collection_check_boxes includes a hidden field with the same name but not value, so that if some checkboxes were checked, then all are unchecked there is something sent to show the application the change in state - else it sees nothing for checkboxes and doesn't update those values.

[atipugin]

+1, same issue :(

[potenza]

This has been fixed with #116. Please let me know if this doesn't work for you...