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.