User member is pointer in TeamJoinEvent

[dvdplm]

Hi,
I just noticed an inconsistency where the UserChangeEvent includes a User(https://github.com/nlopes/slack/blob/master/websocket_misc.go#L40) whereas TeamJoinEvent uses a *User (https://github.com/nlopes/slack/blob/master/websocket_teams.go#L5). Not sure which is better but it'd be great if it was consistent! :)

[joefitzgerald]

I think this all depends on whether the user is a required field or an optional field. If it's required, it should not be a pointer. If it's optional, it should be a pointer.

[dvdplm]

Not sure how you mean "required": it's data sent by Slack (always present for both events and probably for others too) so there's nothing optional about it.

[nlopes]

I think the omitempty should also go as they are always present for both events (I just confirmed this).