Add redis for local dev

[ChrisLovering]

This is required for python-discord/forms-backend#297

[netlify]

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Lighthouse	1 paths audited Performance: 77 (🟢 up 5 from production) Accessibility: 88 (🟢 up 7 from production) Best Practices: 100 (no change from production) SEO: 92 (no change from production) PWA: 80 (no change from production) View the detailed breakdown and full score reports

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