finished database layer

src/types.hpp

@@ -6,10 +6,14 @@
 #include <vector>
 
 #include <clickhouse/client.h>
+#include "clickhouse/base/uuid.h"
 #include "skwyward-api-utils.hpp"
 
 namespace database_utils {
 
+clickhouse::UUID parse_uuid(const std::string& str);
+std::string uuid_to_string(const clickhouse::UUID& u);
+
 // ---------- DB Handle ----------
 
 using CHClient = std::shared_ptr<clickhouse::Client>;
@@ -93,5 +97,7 @@ insert_grade_updates(
     const std::vector<AssignmentDiff>& diffs
 );
 
+std::optional<clickhouse::UUID> get_user_uuid(const CHClient& client, const std::string& username);
+
 } // namespace database_utils