Importing extensions via flask.ext.* is deprecated, use flask_* instead

[jeffwidman]

Details: pallets/flask#1135

[mjhea0]

Thanks @jeffwidman. Will update when I have time.

[leslie-alldridge]

@mjhea0 are you still maintaining this repo? There's a few updates it needs such as this one and issue #14. I'm happy to help merge them over if you're stuck for time.

[mjhea0]

No, I'm not maintaining it anymore. I don't run Real Python anymore. You'll have to check with @dbader .