Roles not working properly

[jahvi]

This might be the reason why #62 is not working but I opened a new issue just in case.

Roles don't seem to be working properly, if you try to add a new role you get the following exception:

Undefined variable: team (View: /var/www/opus/resources/views/team/partials/tab-menu.blade.php)

Also when trying to edit a role:

InvalidArgumentException in FileViewFinder.php line 137: View [role.edit] not found.

And it looks like only the last registered user is getting assigned to the default "admins" role:

Steps to reproduce

1. Create a new team/user.
2. Check roles, there should be 1 user assigned to the admins group.
3. Invite new user, register and login.
4. Check roles, only the newly register user shows up as part of the admins group.

Could it be related to Groups being changed to Roles after ae8e301 and maybe some changes need to be refactored?