diff --git a/main.go b/main.go
index 3204cf6..b4a0cd8 100644
--- a/main.go
+++ b/main.go
@@ -40,25 +40,29 @@ func run(c context.Context, getEnv func(string) string) error {
 	ctx, cancel := signal.NotifyContext(c, os.Interrupt)
 	defer cancel()
 
+	// init sentry
 	if err := sentry.Init(sentry.ClientOptions{
 		Dsn:                getEnv("SENTRY_DSN"),
 		EnableTracing:      true,
 		TracesSampleRate:   1.0,
 		ProfilesSampleRate: 1.0,
 	}); err != nil {
-		return fmt.Errorf("error initializing sentry: %s", err)
+		return fmt.Errorf("error initializing sentry %s", err)
 	}
 
+	// init database
 	db, err := gorm.Open(postgres.Open(getEnv("DATABASE_URL")), &gorm.Config{})
 	if err != nil {
 		return fmt.Errorf("error connecting to the database %s", err)
 	}
 
+	// build booking service
 	err = db.AutoMigrate(&booking.Booking{}, &booking.BookingRequest{}, &booking.Item{})
 	if err != nil {
 		return fmt.Errorf("error migrating the database %s", err)
 	}
 
+	// build pdf service
 	ps, err := pdf.NewPdfService(
 		getEnv("HTMLDOCS_PROJECT_ID"),
 		getEnv("HTMLDOCS_REPORT_PROJECT_ID"),
@@ -69,23 +73,28 @@ func run(c context.Context, getEnv func(string) string) error {
 		return fmt.Errorf("error starting pdf service %s", err)
 	}
 
-	as, err := auth.NewService(getEnv("SESSION_SECRET"), getEnv("ADMIN"), getEnv("ADMIN_SECRET"))
+	// build authentication service
+	as, err := auth.NewService(
+		getEnv("SESSION_SECRET"),
+		getEnv("ADMIN"),
+		getEnv("ADMIN_SECRET"),
+	)
 	if err != nil {
 		return fmt.Errorf("error starting auth service %s", err)
 	}
 
-	creds := os.Getenv("CALENDAR_CREDENTIALS")
-	t2Id := os.Getenv("CALENDAR_ID_T2")
-	t3Id := os.Getenv("CALENDAR_ID_T3")
-
-	cs, err := calendar.NewService(ctx, creds,
-		calendar.WithCalendar("T2", t2Id),
-		calendar.WithCalendar("T3", t3Id),
+	// build calendar service
+	cs, err := calendar.NewService(
+		ctx,
+		getEnv("CALENDAR_CREDENTIALS"),
+		calendar.WithCalendar("T2", getEnv("CALENDAR_ID_T2")),
+		calendar.WithCalendar("T3", getEnv("CALENDAR_ID_T3")),
 	)
 	if err != nil {
-		log.Fatalf("cannot build calendar service: %s", err)
+		log.Fatalf("error starting calendar service %s", err)
 	}
 
+	// starting server
 	p := getEnv("PORT")
 	port, err := strconv.Atoi(p)
 	if err != nil {