Can you add docs on how to use this with jest?

I've tried this:

```
./node_modules/devtool/bin/index.js ./node_modules/jest/bin/jest.js -i
```

Which does launch devtools and runs the tests but I put a `debugger;` line in the code and it didn't stop. I also don't see a way to keep the electron app open so as I save files I can set breakpoints inside the devtools and re-run them.