People might want to use slightly different project schemes. This can range from file extensions and whether to include a particular file (e.g. how .em/config.json works now) to also actually changing the structure completely. It might be a link in the config.json to the generator package. Also need a more modular way for handling different file types. For example, currently if I use the harmony package and have app.next.js files, em thinks it should use coffeescript.