Flaskr tutorial suggestion - Use DATABASE='flaskr' instead of DATABASE='/tmp/flaskr'

[maveryKearney]

Title says it all.
1..DATABASE='flaskr' works for windows and linux
2..DATABASE='/tmp/flaskr' only works for linux and probably OS10

[untitaker]

I think some absolute path for Windows is much more desirable. Not sure what it'd be though.

[mitsuhiko]

/tmp/flask also works on windows if someone creates a folder called "tmp" on the C: drive. But maybe we should change that.

[mitsuhiko]

Not to a relative path though, that's a bad idea since WSGI does not support relative paths.

[untitaker]

See #808

[nachimehta]

Even on OS X '/tmp/flaskr.db' wasn't working. Had to not only create the db file in my project folder but give the absolute path to it as well.. i.e. '/Users/username/path/to/db'