+ def list_users()
+ usernames = []
+
+ begin
+ connection = PGconn.connect(@db_host,
+ @db_port,
+ @db_opts,
+ @db_tty,
+ @db_name,
+ @db_user,
+ @db_pass)
+
+ # User #1 is the super-user, and not tied to an email address.
+ sql_query = "SELECT username FROM usr WHERE user_no > 1"
+
+ connection.query(sql_query) do |result|
+ usernames = result.field_values('username')
+ end
+
+ connection.close()
+ rescue PGError => e
+ # Pretend like we're database-agnostic in case we ever are.
+ raise DatabaseError.new(e)
+ end
+
+ return usernames
+ end
+