Refactor feed into a component.

app/src/components/feed.js

@@ -0,0 +1,18 @@
+import React from "react";
+import { Nav } from "react-bootstrap";
+import { StaticQuery, graphql } from "gatsby"
+import '../styles/sidebar.css'
+import BookCard from "../components/bookcard"
+
+export default ({data, limit}) => {
+    return data.allBooksJson.edges.map(function(x, index) {
+        console.log(index, limit)
+        if(!limit || index < limit){
+            return (
+              <BookCard book={x.node} key={x.node.id} />
+            )
+        } else {
+            return null;
+        }
+    })
+};