Support file uploads

This allows submissions to store file uploads

db/migrate/20200409001610_add_metadata_to_submissions.rb

@@ -0,0 +1,6 @@
+class AddMetadataToSubmissions < ActiveRecord::Migration[6.0]
+  def change
+    add_column :submissions, :remote_ip, :string
+    add_column :submissions, :referrer, :string
+  end
+end