Moving discussion from Google groups to Github

[Robyn Wright]

Hello PICRUSt users! 

In order to try to simplify things moving forwards, we'll be asking everyone to post their questions/comments/issues to Github rather than here. We often get duplicate issues and threads can be quite difficult to keep track of on here. Github also allows a standard format for posting issues where we can request all of the information that we'll need for helping with things over there. 

We won't close this up immediately, but will be asking users to post their issues over on Github when new ones come up. 

Best wishes,

Robyn