+ # Return a list of Roundcube users.
+ #
+ # @return [Array<User>] a list of users contained in the
+ # Roundcube database.
+ #
+ def list_users()
+ usernames = []
+
+ connection = PGconn.connect(@db_host, @db_port, @db_opts, @db_tty,
+ @db_name, @db_user, @db_pass)
+
+ sql_query = 'SELECT username FROM users;'
+ connection.query(sql_query) do |result|
+ usernames = result.field_values('username')