[skip ci]wip file_walker reading article info

sample_data/article/index.md

@@ -2,5 +2,5 @@
 
 ## If you see this page, that means it's working
 
-![missing image](./birthday-cake.png)
+![thumbnail](./birthday-cake.png)
 

src/file_walker.js

@@ -26,9 +26,14 @@ const fileTree = (path, cb) => {
     });
 };
 
+const readIndexFile = (path,cb) => {
+    //TODO reading page title and possibly ![thumbnail](url)
+};
+
 module.exports = (config) => {
     return {
         fileTree: config['test'] ? fileTree : undefined,
+        readIndexFile: config['test'] ? readIndexFile : undefined,
         fetchArticles: (cb) => {
             fileTree(config['data_dir'], (err, fileList) => {
                 if (err)