Add Dropcursor demo for React

demos/src/Extensions/Dropcursor/React/index.jsx

@@ -0,0 +1,20 @@
+import React from 'react'
+import { useEditor, EditorContent } from '@tiptap/react'
+import Document from '@tiptap/extension-document'
+import Paragraph from '@tiptap/extension-paragraph'
+import Text from '@tiptap/extension-text'
+import Dropcursor from '@tiptap/extension-dropcursor'
+import Image from '@tiptap/extension-image'
+import './styles.scss'
+
+export default () => {
+  const editor = useEditor({
+    extensions: [Document, Paragraph, Text, Image, Dropcursor],
+    content: `
+        <p>Try to drag around the image. While you drag, the editor should show a decoration under your cursor. The so called dropcursor.</p>
+        <img src="https://source.unsplash.com/8xznAGy4HcY/800x400" />
+      `,
+  })
+
+  return <EditorContent editor={editor} />
+}