Storybook Implementation

[shawnmath]

• Add storybook dependency. including addon for next.js; created rudimentary Header component & associated story

[llimllib]

Thank you! I've not worked with storybook before, but I like the idea.

Here's what I see when I run this:

Is the idea that we can add more components to it as we go? Is the header supposed to look like something here?

[shawnmath]

Yep, that's right - we'll add stories to components as we create them. I'd think we should make components from the USWDS system.

The refactored Header component is mostly as an example - it accepts children as props, so in the Header story I just added 3 links for display. We can include further variants to display, ie: left or right aligned header items, etc once we iron out what Header should do.

Currently, we can't display static assets in storybook but that is a config issue; I couldn't get to it in this PR. I just wanted to get the implementation up and running.