Adding note for supabase integration

[adilanchian]

Adding note for custom domains and initializing db object.

Closes #

✅ Checklist

• [x] I have followed every step in the contributing guide
• [x] The PR title follows the convention.
• [x] I ran and tested the code works

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Testing

n/a -- was a README change

n/a

Changelog

added a note about the supabase integration and custom domains.

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Screenshots

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[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 5097ab8af840f27feca2b8d8c1dd58a65b8d9405

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