Feature/edit metadata authorization

I assume that pds_handle contain user group name(s) and thus we don't need to add roles. To reflect this I added customized method "groups" to user model. If the assumption is incorrect I will fix it and edit roles file.

@ekate So the single logged_in_users.yml contains two http requests, one that is the FDA cataloger and one that is the GIS cataloger. You could just use the one `@loggedin` tag and that would include both users. If you need to edit those users attrs you could do it directly in the cassette.