Generate and push rubydoc.brew.sh

[MikeMcQuaid]

This is a replacement for the rubydoc.info site that has been a bit unreliable for us.

Also, note we're using the community Ruby style guide now rather than the GitHub one.

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew tests with your changes locally?

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