add ip whitelist to django code example

Example 1: whitelist the ip address django

$ pip install django-ip-restriction

Example 2: whitelist the ip address django

# Django 1.9
MIDDLEWARE_CLASSES = [
    ...
    'ip_restriction.IpWhitelister',
    ...
]

# Django 1.10+
MIDDLEWARE = [
    ...
    'ip_restriction.IpWhitelister',
    ...
]