app: Create basic app.

app/src/components/bookcard.js

@@ -0,0 +1,28 @@
+import { Link } from "gatsby"
+import PropTypes from "prop-types"
+import React from "react"
+
+const BookCard = ({ book }) => (
+    <div key={book.id} class="w-56 rounded overflow-hidden shadow-lg m-3">
+    <img class="w-full" src="https://i.gr-assets.com/images/S/compressed.photo.goodreads.com/books/1414347376l/18050143.jpg" alt="Sunset in the mountains" />
+    <div class="px-6 py-4">
+      <div class="font-bold text-xl mb-2">{ book.title }</div>
+      <p class="text-gray-700 text-base">
+        { book.author }
+      </p>
+    </div>
+    <div class="px-6 py-4">
+      <span class="inline-block bg-blue-200 rounded-full px-3 py-1 text-sm font-semibold text-gray-700 mr-2">{book.category}</span>
+    </div>
+  </div>
+)
+
+BookCard.propTypes = {
+  siteTitle: PropTypes.object,
+}
+
+BookCard.defaultProps = {
+  book:{},
+}
+
+export default BookCard