add support for upload preprocessing

db/migrate/20180517190048_add_missing_fields_to_uploads.rb

@@ -0,0 +1,12 @@
+class AddMissingFieldsToUploads < ActiveRecord::Migration[5.2]
+  def change
+    add_column :uploads, :md5, :string
+    add_column :uploads, :file_ext, :string
+    add_column :uploads, :file_size, :integer
+    add_column :uploads, :image_width, :integer
+    add_column :uploads, :image_height, :integer
+    add_column :uploads, :artist_commentary_desc, :text
+    add_column :uploads, :artist_commentary_title, :text
+    add_column :uploads, :include_artist_commentary, :boolean
+  end
+end

db/migrate/20180518175154_add_context_to_uploads.rb

@@ -0,0 +1,5 @@
+class AddContextToUploads < ActiveRecord::Migration[5.2]
+  def change
+    add_column :uploads, :context, :text
+  end
+end