Update README.md

the backend code resides in the `backend` folder . The flask app is run from inside the backend directory. Using `src` leads to confusion since it is present inside the `frontend` directory.

Author: anantakrroy

backend/README.md

@@ -38,7 +38,7 @@ psql trivia < trivia.psql
 
 ### Run the Server
 
-From within the `./src` directory first ensure you are working using your created virtual environment.
+From within the `./backend` directory first ensure you are working using your created virtual environment.
 
 To run the server, execute: