Prevent upvoting or downvoting multiple times on the same restroom

[translatorzepp]

Context

• Fixes #357
• Basic prevention of double-voting for a restroom.

Summary of Changes

• After up- or downvoting a restroom, store that restroom ID in session and prevent tallying further votes for that restroom
• Add a flash message in English and Spanish

Concerns

• I left off Javascript changes to disable the buttons, but I'd be happy to add it in if folks think it would be nice!
• I think we're safe to put database IDs into session since it's encrypted, but if anyone has concerns about leaking information, let me know.

Checklist

• [x] Tested Mobile Responsiveness
• [x] Added Unit Tests
• [ ] CI Passes
• [ ] Deploys to Heroku on test Correctly (Maintainers will handle)
• [ ] Added Documentation (Service and Code when required)

Screenshots

After

[DeeDeeG]

Thank you for this!

Hopefully @mi-wood or @tkwidmer can take a look at this, since they have dealt with this part of the code more than me. But on first look, this appears pretty good!

I'm not familiar with the Rails session concept, so I'll perhaps take a look into that before merging.

In any case... Happy Hacktoberfest! :jack_o_lantern: :computer: :sparkles: :fallen_leaf:

[DeeDeeG]

Here are some resources about the Rails session feature...

Tutorials, explainers and how-to's: https://www.justinweiss.com/articles/how-rails-sessions-work/ https://www.theodinproject.com/courses/ruby-on-rails/lessons/sessions-cookies-and-authentication https://www.tutorialspoint.com/ruby-on-rails/rails-session-cookies.htm

Official docs: https://guides.rubyonrails.org/action_controller_overview.html#session https://guides.rubyonrails.org/security.html#sessions