multiple roles, in order of apearance

Old way - unnecessary nesting
```ruby
      user.as(AuthSubject) do |auth_user|
        auth_user.as(PasswordResetter) do |reset_user|
          return reset_user.password_reset_token_valid?
        end
      end
```

New way - just list all roles
```ruby
      user.as(AuthSubject, PasswordResetter).password_reset_token_valid?
```