Programmatically calculate the strong params in the jsonform

[ometa]

Right now it's a hack in app/controllers/questions_controller.rb:

  # This is a hack to get around strong parameters.
  # These are the names of the parameter keys in the Race's jsonschema.
  # todo: figure out how to calculate this dynamically.
  HACK_PARAMS = [
    :'racer-type', :'primary-inspiration', :'secondary-inspiration', :'twitter', :'buddies', :'private-comments', :'explain-theme',
    :'agree-to-core-philosophy', :'agree-to-rules', :'agree-to-sabotage', :'agree-to-cart-deposit', :'agree-to-cart-food-poundage',
    :'agree-not-a-donation', :'agree-to-orientation', :'flame-effects', :'fundraising', :'party-bus-interest', :'party-bus-seats'
  ]