#431

backend/app/models/tag_group.rb

@@ -1,5 +1,6 @@
 class TagGroup < ApplicationRecord
   before_create { SharedResourceIdAllocator.assign!(self) }
+  before_destroy :delete_current_structure!
 
   belongs_to :created_by_user, class_name: 'User', optional: true
   belongs_to :updated_by_user, class_name: 'User', optional: true
@@ -15,4 +16,12 @@ class TagGroup < ApplicationRecord
 
   validates :name, presence: true, uniqueness: true, length: { maximum: 255 }
   validates :version_no, numericality: { only_integer: true, greater_than: 0 }
+
+  private
+
+  def delete_current_structure!
+    placements.reorder(position: :desc).each(&:delete)
+    tag_group_tags.delete_all
+    tag_group_groups.delete_all
+  end
 end