Assigns the provided users to the provided queues.
Some relevant information regarding this endpoint:

• The operation is idempotent. If the user already has the queue it becomes a no-op. The API returns success as if the operation went through
• It fails with the appropriate HTTP error code when the request does not conform to the pre-conditions
• Any other failure that is not expected will be reported back in the response of endpoint with a 200 OK.
  This means that consumers always have to check the response to determine if the operation was a success or not (or only partial success)
• The endpoint is not transactional. If some error occurs it might have updated some resources

Pre-conditions

Currently the pre-conditions that are checked are:

• Some invalid user id exists (it does not conform to the ID spec)
• Some queue has over a number of defined (default 100) users in the payload.