Add missing context processor

Needed for some admin functionality, shows up as a warning in 3.2.

pgweb/settings.py

@@ -72,6 +72,7 @@ TEMPLATES = [{
     'DIRS': ['templates', ],
     'OPTIONS': {
         'context_processors': [
+            'django.template.context_processors.request',
             'django.contrib.auth.context_processors.auth',
             'django.contrib.messages.context_processors.messages',
             'django.template.context_processors.media',