Method dbFront

tests/mov_ctor.cc:12–18

	std::unique_ptr<database_binder> storedProcedure;
	database db;
	dbFront(): db(":memory:") {
	    db << "CREATE TABLE tbl (id integer, name string);";
	    // the temporary moved object should not run _execute() function on destruction.
		storedProcedure = std::make_unique<database_binder>(
			db << "INSERT INTO tbl VALUES (?, ?);"
		);
	}
};