Call instance with predefined database prefix

[nickbe]

I'd like to call tinyissue in a iframe like this:

src="http://develop.tinyissue.org/instance/testinstanice1"

tinyissue should then use a predefined storage path variable from the .env section and use a database "(storagepath)/testinstanice1.sqlite"

If it doesn't exist it should throw an error.
This should only work when the instance is started within in an iframe.