database start + cmake policy update

includes/database_service.hpp

@@ -0,0 +1,28 @@
+#ifndef DATABASE_SERVICE_HPP
+#define DATABASE_SERVICE_HPP
+
+#include <boost/asio/io_context.hpp>
+#include <cstddef>
+#include <boost/redis/connection.hpp>
+#include <memory>
+
+class DatabaseService {
+public:
+    static DatabaseService& getInstance(boost::asio::io_context& io_context, std::size_t pool_size);
+
+    
+private:
+    std::shared_ptr<boost::redis::connection> getConnection(); //retrive a connection from the connection pool
+    
+    DatabaseService(boost::asio::io_context& io_context, std::size_t pool_size = 4);
+    ~DatabaseService();
+    DatabaseService(DatabaseService const&);
+    void operator=(DatabaseService const&);
+
+    boost::asio::io_context& io_context_;
+    std::size_t pool_size_;
+    std::vector<std::shared_ptr<boost::redis::connection>> connection_pool_;
+    std::size_t current_index_ = 0; //index used for round robin selection
+};
+
+#endif