Hardcoded local path

I've been unable to get the Froala gem working for me, and so I thought I'd try the example app so I could eliminate a lot of variables and also have a model to look at (in case anything was missing from the README for that gem).

When I cloned this repo and tried running it, I found that it has hardcoded local paths. As far as I can see, there's no good reason for that.

```
$ PORT=3011 rails server
The path `/Users/me/work/wysiwyg-editor-ruby-sdk` does not exist.
```

The problem is in the Gemfile, right at the bottom:

```
# Froala Editor SDK
gem 'froala-editor-sdk', path: '/Users/me/work/wysiwyg-editor-ruby-sdk'
```

Also, is `froala-editor-sdk` just an old version of `wysiwyg-rails`? Since I don't see `wysiwyg-rails` listed in the Gemfile here, I'm guessing that that's the case.

打开 Gemfile 并检查底部的 Froala Editor SDK 依赖；然后运行 PORT=3011 rails server，以复现硬编码路径导致的失败。完成的标准是示例应用不再依赖 /Users/me/work/wysiwyg-editor-ruby-sdk，并且能够在不出现该错误的情况下启动；同时确认示例应用预期使用的是哪个 gem。

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