add markdown story parser

.storybook/lib/storiesFromMarkdown.js

@@ -0,0 +1,16 @@
+import remark from 'remark'
+import select from 'unist-util-select'
+import htmlToReact from 'html-to-react'
+
+export default req => {
+  const parser = new htmlToReact.Parser()
+  return req.keys()
+    .reduce((stories, file) => {
+      const content = req(file)
+      const ast = remark.parse(content)
+      return stories.concat(
+        select(ast, 'code[lang^=html]')
+          .map(node => parser.parse(node.value))
+      )
+    }, [])
+}