Add note about pgtune to install docs

Netdisco/Changes

@@ -13,6 +13,7 @@
   * Clean up library path fiddling across all scripts
   * Rename housekeeping expiry task to be expire
   * Refactor nbtstat to group probes by device where node was arped
+  * Add note about pgtune to install docs
 
   [BUG FIXES]
 

Netdisco/lib/App/Netdisco.pm

@@ -140,6 +140,18 @@ application:
   
  postgres:~$ createdb -O netdisco netdisco
 
+The default PostgreSQL configuration isn't well tuned for modern server
+hardware. We strongly recommend that you use the C<pgtune> Python program to
+auto-tune your C<postgresql.conf> file:
+
+=over 4
+
+=item *
+
+L<https://github.com/elitwin/pgtune>
+
+=back
+
 =head1 Installation
 
 The following is a general guide which works well in most circumstances. It