Join group

Changed schema, there is now a groups collection and a user_groups collection.  The groups collection is the entity that describe the group.  The user_groups collection is a record for each member of a group and describes individual traits that user might have for their membership in a group.  Added last_modified and creation_date to each record.  Promise implimentation.  Also Join group functionality.

After merging please delete all records from the groups collection prior to loading up the dashboard and run npm install.