ForecastModel.aux_data_url field in COVID-19 Forecasts database is set to "Missing" for many models

[matthewcornell]

e.g. https://zoltardata.com/model/370 .Must have been set to that by whoever's script created the models. Fix: SQL to change the field to NULL if it = "Missing".

[matthewcornell]

Ran this SQL on staging and then on production:

SELECT id, abbreviation, aux_data_url
FROM forecast_app_forecastmodel
WHERE aux_data_url = 'Missing';
-- 102 rows

-- CAREFUL!:
UPDATE forecast_app_forecastmodel
SET aux_data_url = NULL
WHERE aux_data_url = 'Missing';
--> UPDATE 102