Vue-CLI / webpack documentation

[joestrouth1]

The readme describes adding a regex to an exclude statement in webpack's config in order to use this with vue-cli.

I'm not sure when things changed, but as of today there is no exclude node_modules statement in their config. They explicitly include src and test instead.

This PR addresses that by adding their current configuration, what needs to be changed to in order to get a successful build, and a brief description of what that's doing/why. I've left the old regex alongside in case someone is using another version.

[tony]

Thank you!

[Justineo]

Sorry guys, I've been overlooking this project for quite long time. The related project Vue-Awesome is being continuously updated. They are almost the same except for the built-in icon set. I think we can either:

1. Switch to Vue-Awesome and just load Octicons as its icon data.
2. or keep Vue-Octicon almost the same with Vue-Awesome.

And also, PRs are welcome.