I needed to setup Flask for windows, so I ran the following commands:

```
set FLASK_APP=application.py
set FLASK_DEBUG=1
set DATABASE_URL='postgres.......' =>(the credential given by the Heroku account)
flask run

```

But when I hit enter on the `flask run`, I get an error that says -

> 
> flask is not recognized as an internal or external command, operable program or batch file
> 
> 
> 

Why is this not working? I've been trying to work on it but I'm still having the same error message.

What could be the issue?