Add debug=True flag for auto-reloading

[Paulinakhew]

From this stackoverflow question and the Flask documentation, you can see that adding debug=True allows for the Flask app to restart each time you make a change to the code

The flask script is nice to start a local development server, but you would have to restart it manually after each change to your code. That is not very nice and Flask can do better. If you enable debug support the server will reload itself on code changes, and it will also provide you with a helpful debugger if things go wrong. Excerpt from Flask documentation

• this is what it looks like when you make a change
  • the server reloads with the new changes