Small fix on Redis section on rails.md

[fernandes]

Actually Redis needs to specify the url: parameter when using the URL, otherwise needs to specify host:, port: so I kept the original example using the URL, but now with the :url option

[rafaelfranca]

I'd leave the sidekiq section our of this documentation since it is too specific. Other change seems good.

Thanks

[fernandes]

hey @rafaelfranca thank you for the feedback... removed the last commit, so I think now its ok

[rafaelfranca]

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[fernandes]

thanks :heart: :green_heart: :blue_heart: :yellow_heart: :purple_heart: