add custom validations for owner role

* edit role information for user
something sometihng something duplication. Totally could be rewritten to be `user_tagline(user)` helper or in the model or sometihng.

Then you can have a 
```ruby
<% if current_user.user.can_add_employees? %>
   <%= link_to "Add Employee", new_location_user_path(location) %>
<% end %>
```