def add_app(self, module_name):

        cls = AppBase.find(module_name)
        if cls is None: return None

        app = cls(self)
        self.apps.append(app)
        return app
Find the app named *module_name*, instantiate it, and add it to
dataset/ETHPy150Open rapidsms/rapidsms-core-dev/lib/rapidsms/router.py/Router.add_app