active storage deletes multi-file uploads. now you can upload assets in a single assets array and it appends them to the existing files instead of deleting them--what we normally expect. now to add a delete file/delete asset button

Author: azeemh

app/models/concerns/append_to_has_many_attached.rb

@@ -0,0 +1,21 @@
+module AppendToHasManyAttached
+  def self.[](fields)
+    Module.new do
+      extend ActiveSupport::Concern
+
+      fields = Array(fields).compact_blank # will always return an array ( worst case is an empty array)
+
+      fields.each do |field|
+        field = field.to_s # We need the string version
+        define_method :"#{field}=" do |attachables|
+          attachables = Array(attachables).compact_blank
+
+          if attachables.any?
+            attachment_changes[field] =
+              ActiveStorage::Attached::Changes::CreateMany.new(field, self, public_send(field).public_send(:blobs) + attachables)
+          end
+        end
+      end
+    end
+  end
+end

app/models/story.rb

@@ -1,11 +1,17 @@
 class Story < ApplicationRecord
+  include AppendToHasManyAttached['articleassets'] # you can include it before or after, order does not matter, explanation below
+
   belongs_to :user
   belongs_to :category
   has_one_attached :image
   has_one_attached :video
   has_one_attached :audio
   has_many_attached :articleassets
 
+  def append_files=(attachables)
+    articleassets.attach(attachables)
+  end
+
   validates :autopublishdate, presence: true, if: :enableautopublish?
   validates :title, presence: true, uniqueness: { case_sensitive: false }
   validates :content, presence:true