upload files about Product.
scaffold Genre
define relation Product to Genre.
move label creation logic from LabelCreator to Product
delete css
rename column, define attr_accesser
change method name.
move file save logic from controller to model.
use custom validate method for format check.
optimeze where and pluck statement.
delete unused source.
Merge pull request #6 from aratana/feature/file-upload

upload files about Product.