Define RWS::BaseGenre class
Change the superclass of Books::Genre to RWS::BaseGenre
Fix a bug: param key couldn't be converted to camelcase from snakecase
Refactoring convert_snake_key_to_camel_key
Replaces RWS::Books::Genre.new with RWS::BaseGenre
BaseGenre.root_id allows to define root genre id for each API
Merge pull request #4 from rakuten-ws/abstract_genre_resource

Define RWS::BaseGenre