Replace a database with the data from the specified source.

def run(self):
        """ Replace a database with the data from the specified source. """
        self.print_message("\nBeginning database replacement process.\n")

        if self.args.source_settings:
            settings = self.parse_db_settings(self.args.source_settings)
            self.initialize_db_args(settings, 'source')

        if self.args.settings:
            settings = self.parse_db_settings(self.args.settings)
            self.initialize_db_args(settings, 'destination')

        if self.args.capture:
            self.capture_heroku_database()

        file_url = self.args.url
        if self.args.source_app:
            self.print_message("Sourcing data from backup for Heroku app '%s'"
                               % self.args.source_app)
            file_url = self.get_file_url_for_heroku_app(self.args.source_app)

        if self.args.destination_app:
            self.replace_heroku_db(file_url)
        elif self.databases['destination']['name']:
            self.replace_postgres_db(file_url)

        self.print_message("\nDone.\n\nDon't forget to update the Django Site entry if necessary!")