feat: add postgres repository for training

internal/server/server.go

@@ -3,6 +3,7 @@ package server
 import (
 	"context"
 	"fmt"
+	"github.com/jackc/pgx/v5/pgxpool"
 	"time"
 
 	fiberzap "github.com/gofiber/contrib/fiberzap/v2"
@@ -16,13 +17,15 @@ type Server struct {
 	port        int
 	logger      *zap.Logger
 	apiHandlers *APIHandlers
+	pool        *pgxpool.Pool
 }
 
-func NewServer(apiHandlers *APIHandlers, port int, logger *zap.Logger) *Server {
+func NewServer(apiHandlers *APIHandlers, port int, logger *zap.Logger, pool *pgxpool.Pool) *Server {
 	return &Server{
 		apiHandlers: apiHandlers,
 		port:        port,
 		logger:      logger,
+		pool:        pool,
 	}
 }
 
@@ -54,6 +57,11 @@ func (s *Server) Run(ctx context.Context) {
 		panic(err)
 	}
 
+	// gracefully shutdown/close database pool
+	if s.pool != nil {
+		s.pool.Close()
+	}
+
 	s.logger.Info("HTTP server shut down gracefully.", zap.Duration("duration", time.Since(shutdownBegan)))
 }