george/prediction_tracker: Manage and score predictions on arbitrary topics. @ 27ac386c9307fb52f36e3887695cd2030b43fb9c

George C. Privon 27ac386c93 implement adding predictions		6 vuotta sitten
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brier_score.rkt	88e68619e7 Brier score and unit test	6 vuotta sitten
create_database.rkt	3b8fae716c don't force entry of prediction text every time, since prediction has unique ID	6 vuotta sitten
update_predictions.rkt	27ac386c93 implement adding predictions	6 vuotta sitten