Carbon frame chipped by chain - how to repair? I found out my chain is damaging my frame near the cassette. How can I repair this?

It was damaged by my cassette in the indoor trainer which I am not using anymore. 
This is how it looks:
I wouldn't worry about it too much. Most Carbon fiber bike frames utilize some form of alloy dropouts. What you are seeing here is merely cosmetic damage and is unlikely to affect the bike in any way unless you deliberately continue to expose that part to damage.
For repair, I would consider a light coat of epoxy which you could even out and spray paint afterwards to minimize the aesthetic imperfection.