I haven't found the npm command in your readme to install the webpack so I've entered the github repository name into the npm registry. But there you can only find grunt-webpack, so I was assuming I need grunt to run the module. After some research I've read the npm instructions in your readme by coincidence.

It's very confusing that this module is called modules-webpack on github and you're installing it via npm install webpack. I think the best solution would be to rename the repository to webpack and make the npm installation instructions more obvious. In addition it's very common to have a chapter Installlation right after the short description. Even though this module seems to be designed for all CommonJS-modules, the nodejs use-case will be the most usual.

However, your module is very interesting! :) Currently I'm doing some evaluation to find out if it's useful for my company.