Update app.py

app.py

@@ -1,4 +1,6 @@
-import subprocess, os, shutil, time, sys
+import subprocess, os, shutil, time, sys, platform
+if platform.system() == 'Windows':
+    raise SystemError("You are trying to run this demo on **Windows**. Windows is not supported. If you would still like to try, remove lines 2 & 3 in the code to bypass this warning.")
 
 def setup_virtual_env():
     # Create a virtual environment directory