Improve handling of unexpected data passed to EventsController.

[somazx]

Hi,

Should there be some sort of sanity check that events_json decodes to an Array?

We noticed a number of errors reported in our exception logging related to events_controller.rb:25 where the code expects an instance of array. Some values passed in as param events_json will result in the code reaching this point with a nil or integer value instead of an instance of array.

In our case, this was the byproduct of automated fuzzing/penetration testing by a bot (Detectify).

undefined method `first' for nil:NilClass

params:

{
  "action": "create",
  "controller": "ahoy/events",
  "events_json": "nil"
}

undefined method `first' for 41414141:Integer

params

{
  "action": "create",
  "controller": "ahoy/events",
  "events_json": "41414141"
}