Correct all some error.
md5 password.
Add mongose in package.json.
Config mongodb.
Add user model.
Add  method for user class.
Remove mongooes.
Now wen can save resister to mongo db.
Add a helper to check error message.
Now we can display error message if email have beed used.
Now we can redirect to homepage when register successfully.
Add path_config.js to save path.