initial commit

app/controllers/api/attachments_controller.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module Api
+  class AttachmentsController < ApiBaseController
+    skip_before_action :authenticate_user!
+
+    def create
+      submission = Submission.find_by!(slug: params[:submission_slug])
+      blob = ActiveStorage::Blob.find_signed(params[:blob_signed_id])
+
+      attachment = ActiveStorage::Attachment.create!(
+        blob:,
+        name: params[:name],
+        record: submission
+      )
+
+      render json: attachment.as_json(only: %i[uuid], methods: %i[url filename content_type])
+    end
+  end
+end