Scaffold basic workshop frontend.

lib/remark-extract-frontmatter.js

@@ -0,0 +1,10 @@
+import { visit } from 'unist-util-visit'
+import { load } from 'js-yaml'
+
+export default function extractFrontmatter() {
+  return (tree, file) => {
+    visit(tree, 'yaml', (node, index, parent) => {
+      file.data.frontmatter = load(node.value)
+    })
+  }
+}