readme: Add note about updating and password gen

docs/README

 
 Modify the config file as you like.
 
+To generate passwords for opers and connect passwords, you can use this command:
+
+    $ oragono genpasswd
+
 Run these commands in order -- these will setup each section of the server:
 
     $ oragono initdb
     $ oragono run
 
 And you should now be running Oragono!
+
+
+=== Updating ===
+
+If you're updating from a previous version of Oragono, checkout the CHANGELOG for a shortlist
+of important changes you'll want to take a look at. The change log details config changes,
+fixes, new features and anything else you'll want to be aware of!
+
+If there's been a database update, you'll also need to run this command:
+
+    $ oragono upgradedb