add gitignore
fix typo
fix file path
refactor
fix dart error

Exception: 'http://localhost:8080/Application.dart': malformed type: line 17 pos 20: type 'AppModule' is not loaded
    .addModule(new AppModule())
                   ^
type error.
fix dart error

Exception: Class '_StaticApplication' has no instance method 'addMdoule'.

NoSuchMethodError: method not found: 'addMdoule'
Receiver: Instance of '_StaticApplication'
Arguments: [Instance of 'NodeBindModule']
update polymer to >=0.12.0-dev <0.12.0
add pubspec.lock