Add a required inline on django admin

[zodman]

Here more detailed info:

​http://stackoverflow.com/questions/1206903/how-do-i-require-an-inline-in-the-django-admin

I propouse to use some like this:

class ProfileInline(admin.StackedInline):
    """
    Allows profile to be added when creating user
    """
    model = Profile
    extra = 1
    max_num = 1
    formset = RequiredInlineFormSet
    formset_required = True