Add the conservancy-www-db.path Systemd file

This runs the SQL update when the relevant file is modified.

systemd/README.md

@@ -1,8 +1,8 @@
-# SystemD services
+# Systemd services
 
 ## Installing
 
-Install all SystemD services with:
+Install all Systemd services with:
 
     cp systemd/conservancy-www-*.{service,timer} /etc/systemd/system
     systemctl enable conservancy-www-cleanup.service
@@ -10,6 +10,7 @@ Install all SystemD services with:
     systemctl enable conservancy-www-update.timer
     systemctl start conservancy-www-update.timer
     systemctl enable conservancy-www-db.service
+    systemctl start conservancy-www-db.path
 
 
 ##  Website updates
@@ -29,6 +30,6 @@ Note that the update script does not run `migrate`.
 
 ## Fundraiser/sustainer database updates
 
-The `conservancy-www-db.service` applies SQL updates to the website
-database. These include the fundraising total and sustainers to be publicly
-acknowledged.
+The `conservancy-www-db.service` applies SQL updates to the website database
+automatically when the file `django-supporters-list.sql` file is modified. These
+include the fundraising total and sustainers to be publicly acknowledged.

systemd/conservancy-www-db.path

@@ -0,0 +1,9 @@
+[Unit]
+Description=Update Conservancy website database
+Before=apache2.service
+
+[Path]
+PathChanged=/home/debian/django-supporters-list.sql
+
+[Install]
+WantedBy=apache2.service