Use with offline-plugin

Is there a working example of `isomorphic-webpack` + [`offline-plugin`](https://github.com/NekR/offline-plugin) anyone might be able to share? I encounter this error when trying to use `offline-plugin` in my `isomorphic-webpack` app:

```
/home/tyler/Projects/webpack2test/node_modules/offline-plugin/runtime.js:3
if (window.console) {
^

ReferenceError: window is not defined
at Object. (/home/tyler/Projects/webpack2test/node_modules/offline-plugin/runtime.js:3:5)
```

:arrow_up: In this case, I added the `require('offline-plugin/runtime').install()` line to my entry file, before the app client itself (`index.jsx`).

If I try to install the plugin/runtime in `index.jsx` itself (instead of in the webpack entry just before `index.jsx`), I end up with an error like this :arrow_down:

```
TypeError: Cannot read property './index.jsx' of undefined
at evalBundleCode (/home/tyler/Projects/webpack2test/node_modules/isomorphic-webpack/dist/factories/createIsomorphicWebpack.js:133:37)
at /home/tyler/Projects/webpack2test/src/server/server.js:141:21
at Layer.handle [as handle_request] (/home/tyler/Projects/webpack2test/node_modules/router/lib/layer.js:93:5)
```

I realise this isn't exactly a problem with `isomorphic-webpack` itself, but I imagine I'll have better luck here than their repo. I'd be happy to provide some code to play with if it would help

(Alternatively: anyone have suggestions for building this offline functionality without this plugin?)