Support file uploads

This allows submissions to store file uploads

app/models/submission.rb

@@ -1,17 +1,20 @@
 class Submission < ApplicationRecord
   belongs_to :form
-  after_create :append_to_spreadsheet
-  validates_presence_of :data
+  has_many :file_uploads, dependent: :destroy
+  has_many_attached :files
 
-  def data=(value)
-    sanitized_data = {}
-    value.each do |key, value|
-      sanitized_data[key] = submission_value(value)
+  validates_presence_of :data, if: :appended_at?
+
+  def process_data(submitted_data)
+    processed_data = {}
+    submitted_data.each do |key, value|
+      processed_data[key] = submission_value_for(value)
     end
-    write_attribute(:data, sanitized_data)
+    update_attribute(:data, processed_data)
+    SubmissionAppendJob.perform_later(self.id)
   end
 
-  def submission_value(value)
+  def submission_value_for(value)
     case value
     when Array
       value.join(', ')
@@ -20,7 +23,16 @@ class Submission < ApplicationRecord
     when 'tinyforms_now'
       Time.now.utc.to_formatted_s(:rfc822)
     when ActionDispatch::Http::UploadedFile
-      ''
+      # manually create the ActiveStorage attachment because we need the ID of the Attachment to create the URL
+      # first the file needs to be uplaoded then we can create an Attachment
+      # The CreateOne mainly handles the uplaod and the creation of the blob for us
+      # `files` is the name from `has_many_attached :files`
+      create_one = ActiveStorage::Attached::Changes::CreateOne.new('files', self, value)
+      create_one.upload
+      attachment = ActiveStorage::Attachment.new(record: self, name: 'files', blob: create_one.blob)
+      attachment.save
+      # return the URL that we use to show in the Spreadsheet
+      Rails.application.routes.url_helpers.file_upload_url(form_id: form, submission_id: self, id: attachment.id, host: DEFAULT_HOST)
     else
       value.to_s
     end