Delete a case from the database

        Args:
            case_obj (puzzle.models.Case): initialized case model

def delete_case(self, case_obj):
        """Delete a case from the database

        Args:
            case_obj (puzzle.models.Case): initialized case model
        """
        for ind_obj in case_obj.individuals:
            self.delete_individual(ind_obj)
        logger.info("Deleting case {0} from database".format(case_obj.case_id))
        self.session.delete(case_obj)
        self.save()
        return case_obj