Add vercel deployment configs

app.py

@@ -0,0 +1 @@
+from backend import app

vercel.json

@@ -0,0 +1,4 @@
+{
+  "builds": [{ "src": "app.py", "use": "@vercel/python" }],
+  "routes": [{ "src": "/(.*)", "dest": "app.py" }]
+}