Add CodeSandbox for query parameter

Author: chvmvd

docs/3-web-servers/06-form/_samples/query-parameter/.gitignore

@@ -0,0 +1 @@
+node_modules

docs/3-web-servers/06-form/_samples/query-parameter/main.mjs

@@ -0,0 +1,7 @@
+import express from "express";
+
+const app = express();
+app.get("/", (request, response) => {
+  response.send(JSON.stringify(request.query));
+});
+app.listen(3000);