k0r0g

class RegRouter:
    def db_for_read(self, model, **hints):
        if model._meta.db_table == 'registrations_table':
            return 'registrations'
        return None

    def db_for_write(self, model, **hints):
        if model._meta.db_table == 'registrations_table':
            return 'registrations'
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        if db == 'registrations' and model_name == 'registration':
            return True
        if db == 'registrations' and model_name != 'registration':
            return False
        if db == 'default' and model_name == 'registration':
            return False
        else:
            return True