[Fix #199] Fix the homepage URI

[koic]

Fixes #199.

This PR fixes the homepage URI.

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Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[andyw8]

Perhaps also worth adding to the README?

[koic]

That is a good idea! It will help users if added like the RuboCop core.
https://github.com/rubocop-hq/rubocop#documentation

[bbatsov]

Nice catch! It's pretty weird this doesn't work without the trailing slash. Oh, well... One more argument to abandon ReadTheDocs at some point.

[koic]

Sure. ReadTheDocs may have changed. I have no opinion as there is no knowledge of a services that provide documentation.

[bbatsov]

@koic I've migrated a while ago one of my other major projects to Antora (AsciiDoc) and I've been pretty happy with the results (see https://docs.cider.mx). Notice is the menu how you can easily switch between the docs for related projects and how much better doc search is. That's also why I moved the style guides from Markdown to AsciiDoc (btw, these days the canonical AsciiDoc implementation is written in Ruby, which is pretty cool). The only real problem is that converting between the two formats is a lot of work, as the auto-conversion is not precise and we'd have to update the cop docs generation logic as well.