Add postgresql support

src/database/sqlite3_engine.hpp

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <database/engine.hpp>
+
+#include <database/statement.hpp>
+
+#include <sqlite3.h>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <set>
+
+class Sqlite3Engine: public DatabaseEngine
+{
+ public:
+  Sqlite3Engine(sqlite3* db);
+
+  ~Sqlite3Engine();
+
+  static std::unique_ptr<DatabaseEngine> open(const std::string& string);
+
+  std::set<std::string> get_all_columns_from_table(const std::string& table_name) override final;
+  std::tuple<bool, std::string> raw_exec(const std::string& query) override final;
+  std::unique_ptr<Statement> prepare(const std::string& query) override;
+  void extract_last_insert_rowid(Statement& statement) override;
+  std::string id_column_type() override;
+private:
+  sqlite3* const db;
+};
+