add legacy warning

Author: leonardoventurini

scripts/legacy-warning.js

@@ -0,0 +1,11 @@
+/* global hexo */
+
+hexo.extend.filter.register('after_render:html', function (str) {
+  const warningMessage = `
+    <div style="text-align: center; padding: 10px; width: 100%; color: lightcoral">
+      ⚠️ This is a legacy version of the React tutorial. Please visit <a href="https://docs.meteor.com/tutorials/react/" style="color: coral">docs.meteor.com/tutorials/react</a> for the current version.
+    </div>
+  `;
+
+  return str.replace(/<div class="content">/, `<div class="content" data-injected>${warningMessage}`);
+});