README lacks config documentation

Hi, I can't add a StackOverflow question because the tag is too long.

I'm having problems configuring babel-plugin-react-css-modules with Webpack v2.5 There doesn't seem to be any documentation on how to set it up and the demo given doesn't work with webpack 2.5 (can't provide query inside loaders anymore).

Here's what I have right now in my webpack config:
```
{
test: /\.s?css$/,
loaders: [
'style-loader?sourceMap',
'css-loader?modules&importLoaders=1&localIdentName=' +
'[path]___[name]__[local]___[hash:base64:5]'
]
},
```
And in my .babelrc I have:
```
"plugins": [
"react-css-modules"
],
```
(If I leave the babelrc reference out, I don't get any classes added)

The issue I'm facing is that the classes in the stylesheet don't match the classes applied to the element. Presumably because the context is not correct. But I don't know how to specify the context within webpack config.