app/views/relations/_relation_fields.html.haml
%fieldset
.field
= f.label :relationship_dataset_description_id, t('dataset.relationship_dataset_description')
= f.grouped_collection_select :relationship_dataset_description_id, DatasetCategory.all, :dataset_descriptions, :title, :id, :title, :inline => true
.field
= f.check_box :morph
%br
= f.hidden_field :_destroy
= submit_tag "- ##{index}", name: "remove_relation", class: 'remove_element'