How to setup `websocket_frontend_path` and `websocket_backend_path`?

[dmitrii_fediuk]

> Incenteev\ParameterHandler\ScriptHandler::buildParameters
Updating the "app/config/parameters.yml" file
Some parameters are missing. Please provide them.
websocket_frontend_path (''):

[dmitrii_fediuk]

I have just used empty values for them: