Update app.js

@@ -89,7 +89,7 @@ async function handleEvent(event) {
       client.getMessageContent(event.message.id)
       .then((stream) => {
         stream.on('data', (chunk) => {
-          fs.writeFileSync('/photo/1.png',chunk);       
+          fs.writeFileSync('./photo/1.png',chunk);       
         });
       });
       
@@ -106,7 +106,7 @@ async function handleEvent(event) {
           'Content-Type': 'application/json',
           'Ocp-Apim-Subscription-Key': '979dc5d63344438fa4701c62feebb7dc'
         },
-      body: fs.readFileSync('/photo/1.png')
+      body: fs.readFileSync('./photo/1.png')
       };
       console.log(body);
       request.post(options, function (error, response, body) {