PUSH QuestionAnsweredEvent object

Represents the answering of a drill question by a user.

Field	Type	Description
`eventId` required	String	The unique ID of the event.
`eventType` required	String	The type of the event (`QUESTION_ANSWERED`).
`user` required	PUSH User objects	The user who answered the question.
`playable` required	PUSH Playable objects	A reference to the learning object.
`correct` required	Boolean	Whether the given answer was correct.
`date` required	Timestamp	A timestamp for the event.