Add sample JSON file

[Ruborcalor]

Add test credentials that allow for one to explore the functionality of Aspine without exposing a real person's username and password / grades.

[psvenk]

It might be a good idea to have this implemented as a button (or other UI control) instead of credentials, to avoid a collision with a real username (particularly with #80 implemented) and so that it does not seem as though the credentials are being sent over to the Aspen instance.

[psvenk]

Perhaps this could be merged with #74, in that there could be a button on the login page to continue without sending credentials to Aspen, and we could then offer the options of continuing with the test account (a provided JSON export) or uploading one's own JSON export.

[notrodes]

A username collision cannot happen if the username is a format that is normally invalid for aspen, i.e. "bob".

[psvenk]

A username collision cannot happen if the username is a format that is normally invalid for aspen, i.e. "bob".

The problem with that is that we would be assuming that "bob" is invalid. ICTS could change the username format as they have done in the past. If a teacher's first initial is "B" and last name is "Ob", then "bob" would be a valid username under the current scheme (which may become important for us, if enough teachers are interested in having a teacher adaptation of Aspine).

[psvenk]

@notrodes This is not necessarily a backend issue, as nothing is being scraped from Aspen.

[psvenk]

This can be implemented as a suggested sample JSON file once #74 is merged. I have already begun working on such a file, but it is far from complete.