Add social integration options to GA track

I need to use [GA's social interactions](https://developers.google.com/analytics/devguides/collection/analyticsjs/social-interactions), but `analytics.track(...)` doesn't appear to support that event type just yet. For now, I'm still calling it like `ga('send', 'social', ...)`.

Could something like this be added, or is there an existing method I'm missing?