[MySQL] Replace single server deployment with flexible server

Author: markingmyname

articles/mysql/.openpublishing.redirection.mysql.json

@@ -774,6 +774,11 @@
         "source_path_from_root": "/articles/mysql/flexible-server/index.yml",
         "redirect_url": "/azure/mysql/index",
         "redirect_document_id": false
+    },
+    {
+        "source_path_from_root": "/articles/mysql/single-server/quickstart-create-mysql-server-database-using-azure-portal.md",
+        "redirect_url": "/azure/mysql/flexible-server/quickstart-create-server-portal",
+        "redirect_document_id": false
     }
   ]
 }