Rework auth for private groups 

Using the `auth` branch. Add to the user schema to have **authenticatedGroups** so whenever a user is logged to any device they will be able to join group without password. 

Also if you're up for even more of a challenge we need to add another field (**adminGroups**) so when a user creates a group it adds to that users schema.

If you've got any questions please reach out.