flask websockets example on diesel.io home page doesn't run

[davidthewatson]

I couldn't find the flask example on diesel.io homepage in git or I'd have diffed it and issued a pull request. At any rate, it's missing:

from diesel.util.queue import deque

at the beginning

and

app.run(debug=True)

at the end

[gabeio]

it only needs an
app.run()
the debug is unneeded