Add a description how to setup eslint-plugin-vue on style guide page

[re-fort]

Looking at the eslint-plugin-vue demo, it seems that the rules of priority A to C are already added.
I think it is about time to add a description how to setup eslint-plugin-vue on style guide page.
Or wait till the priority D rules have been added?

[chrisvfritz]

Yes, this is on my todo list! 😅 Priority D rules will possibly never be added to the ESLint plugin, since they're a bit more difficult to detect, but I do want to add links to the corresponding ESLint rules where they exist. 🙂

[jamessouth]

😆 I didn't know this existed so I published vue-style-lint. It only does one thing but I guess I'll stop working on it.