Initializes Ask app by setting configuration variables and maps RAK route to a flask view.
        The RAK instance is given the following configuration variables by calling on Flask's configuration:

def init_app(self, app):
        """Initializes Ask app by setting configuration variables and maps RAK route to a flask view.
        The RAK instance is given the following configuration variables by calling on Flask's configuration:

        """
        if self._route is None:
            raise TypeError(
                "route is a required argument when app is not None")

        app.rak = self
        app.add_url_rule(self._route, view_func=getattr(self, self._view_name), methods=['POST'])