It’s probably also a good idea to remove uploads:
rm -fr public/uploads
I once leaked a load of virus-infected uploads from one site I imported to another client. 
Here is a gist of my new_discourse_database script that kills any running rubies (you can’t drop the database if rails s is running), deletes uploads, makes the new database, and sets an admin user and password. It also prints an obnoxious warning and waits 5 seconds since I’ve run it by mistake a few times too many.