I like this, but I prefer having this custom relay in a setting or config file, so that someone doesn't have to change the code, to dislodge that relay.
Discussion
I agree, it should be configurable. The default relay an app ships with should be a starting point, but the app should preserve the user's freedom to read from any relay he or she wishes.
Having a default relay intended to handle the types of events the app is built for gives a better user experience at the outset, as users don't need to manually configure a relay set to start seeing things on the app.