cove_project: settings: Add memcached backend if not in DEBUG mode

Add with defaults as suggested in Django documentation.

Related: open-contracting/cove-ocds#90

README.md

@@ -1,5 +1,13 @@
 # cove-oc4ids
 
+## Production installation
+
+We recommened deploying [Django using uWSGI](https://docs.djangoproject.com/en/2.2/howto/deployment/wsgi/uwsgi/) and [Apache http server using mod_proxy](https://uwsgi-docs.readthedocs.io/en/latest/Apache.html#mod-proxy-uwsgi)
+
+### Caching
+
+In non-dev or not DEBUG mode the default settings make use of a local memcached server. This backend requires an additional dependency of `python-memcached` as well as memcached server running. On debian based systems this can be installed with `apt install memcached`.
+
 ## Dev installation
 
     git clone https://github.com/open-contracting/cove-oc4ids.git

cove_project/settings.py

@@ -54,6 +54,7 @@
 
 
 MIDDLEWARE = (
+    'django.middleware.cache.UpdateCacheMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
     'django.middleware.locale.LocaleMiddleware',
     'django.middleware.common.CommonMiddleware',
@@ -64,6 +65,7 @@
     'django.middleware.security.SecurityMiddleware',
     'dealer.contrib.django.Middleware',
     'cove.middleware.CoveConfigCurrentApp',
+    'django.middleware.cache.FetchFromCacheMiddleware',
 )
 
 
@@ -159,3 +161,14 @@
 # https://github.com/open-contracting/deploy/issues/188
 CSRF_COOKIE_NAME = 'oc4idscsrftoken'
 SESSION_COOKIE_NAME = 'oc4idssessionid'
+
+if not DEBUG:
+    CACHES = {
+        'default': {
+            'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
+            'LOCATION': '127.0.0.1:11211',
+            'OPTIONS': {
+                'server_max_value_length': 1024 * 1024 * 2,
+            }
+        }
+    }