Add package uploader [ci skip]

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/models/packages/package_file.rb

 class Packages::PackageFile < ActiveRecord::Base
   belongs_to :package
+
+  mount_uploader :file, PackageFileUploader
 end

app/uploaders/packages/package_file_uploader.rb

+class Packages::PackageFileUploader < GitlabUploader
+  extend Workhorse::UploadPath
+  include ObjectStorage::Concern
+
+  # TODO: Implement me
+end

db/migrate/20180720120026_create_packages_package_files.rb

@@ -6,6 +6,7 @@ class CreatePackagesPackageFiles < ActiveRecord::Migration
       t.references :package, index: true, foreign_key: { on_delete: :cascade }, null: false
       t.string :file
       t.integer :file_type
+      t.integer :file_store
       t.integer :size
       t.binary :file_md5
       t.binary :file_sha1