Fixes exception for missing react import
Fixes exception for missing react import

By importing React in tags.jsx, this issue is fixed:
```javascript
 React::ServerRendering::PrerenderError:
   Encountered error "#<ExecJS::ProgramError: ReferenceError: React is not defined>" when prerendering <component-name> with {}
   HiddenFieldTag ((execjs):588:3)
```

danott/react-rails-form-helpers