@sawanoboly Thanks for adding documentation!

Can I get you to move this file to `lib/fog/sakuracloud/docs`? We are trying to pull all of our provider specific documentation in `PROVIDER/docs` and all of our examples into `PROVIDER/examples`.

And once this PR is accepted can you submit another PR to [fog.github.com](fog.github.com) to add a link to your documentation on the [provider documentation page](https://github.com/fog/fog.github.com/blob/master/about/provider_documentation.markdown). That way developers can find your document from [fog.io](fog.io).