switch to pgx driver + create merch

internal/user/handler.go

@@ -1,7 +1,7 @@
 package user
 
 import (
-	"database/sql"
+	"github.com/jackc/pgx/v5/pgxpool"
 	"merch-api/pkg/utils"
 )
 
@@ -10,7 +10,7 @@ type Handler struct {
 }
 
 type Deps struct {
-	DB    *sql.DB
+	DB    *pgxpool.Pool
 	Utils utils.Utils
 }