Add referrer package and middleware

opentech/settings/base.py

@@ -139,6 +139,7 @@ MIDDLEWARE = [
     'django.contrib.auth.middleware.AuthenticationMiddleware',
     'django.contrib.messages.middleware.MessageMiddleware',
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
+    'django_referrer_policy.middleware.ReferrerPolicyMiddleware',
 
     'opentech.apply.users.middleware.SocialAuthExceptionMiddleware',
 

requirements.txt

@@ -32,6 +32,7 @@ dj-database-url==0.5.0
 django-basic-auth-ip-whitelist==0.2.1
 django-heroku==0.3.1
 django-redis==4.9.0
+django-referrer-policy==1.0
 whitenoise==4.0
 gunicorn==19.9.0
 ConcurrentLogHandler==0.9.1