def __init__(self):

        db = Database('database')

        if db .root is None:

            root = Persistent()
            root.list_of_users = []
            db.elect (root)
            transaction.commit()

            checkout(db.root)

            self.list_of_users = db.root.list_of_users

            # Creating a user default to make easy the development
            user = User('Fulano', '*****@*****.**', 'pwd', "uid")

            document = Document("My document", ".txt", "I think to myself... what a wonderful world!", "uid", user.folder.id)
            document.id = "did"
            user.folder.id = "fid"
            user.add_document(user.folder.id, document)

            db.root.list_of_users.append(user)
            db.root.list_of_users = self.list_of_users

            transaction.commit()

            checkout(db .root)

            self.list_of_users = db .root.list_of_users
        else:
            self.list_of_users = db.root.list_of_users
        super(UserRepository, self).__init__()