Use hashing to associate sessions

TEMPLATE.env

@@ -33,6 +33,10 @@ SCRIPT_USE_HTTPS=True
 # How frequently should the monitoring script "phone home" (in ms)?
 SCRIPT_HEARTBEAT_FREQUENCY=5000
 
+# How much time can elapse between requests from the same user before a new
+# session is created, in seconds?
+SESSION_MEMORY_TIMEOUT=1800
+
 # Should only superusers (admins) be able to create services? This is helpful
 # when you'd like to invite others to your Shynet instance but don't want
 # them to be able to create services of their own.