Fix wsgi documentation

docs/wsgi.md

@@ -5,19 +5,22 @@ Install `apache2` and `libapache2-mod-wsgi`
 
 We'll set up the database server at URL `http://myhost.com/nilmdb`.
 The database will be stored in `/home/nilm/db`, and the process will
-run as user `nilm`.
+run as user `nilm`, group `nilm`.
 
 First, create a WSGI script `/home/nilm/nilmdb.wsgi` containing:
 
     import nilmdb.server
-    application = nilmdb.server.wsgi_application("/home/nilm/db")
+    application = nilmdb.server.wsgi_application("/home/nilm/db", "/nilmdb")
+
+The first parameter is the local filesystem path, and the second
+parameter is the path part of the URL.
 
 Then, set up Apache with a configuration like:
 
     <VirtualHost>
         WSGIScriptAlias /nilmdb /home/nilm/nilmdb.wsgi
-        WSGIProcessGroup nilmdb
-        WSGIDaemonProcess nilmdb threads=32 user=nilm
+        WSGIProcessGroup nilmdb-server
+        WSGIDaemonProcess nilmdb-server threads=32 user=nilm group=nilm
 
         # Access control example:
         <Location /nilmdb>