Update #843 - Adds backend for Discord integration

[kondanna]

This is a resubmission since I deleted my forked repo & its branches.

adds utility functions for fetching data
adds refresh token to User table

can't get the fetch tests to pass - the fetches never resolve and will throw error in both cases

[vercel]

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[codecov]

Codecov Report

Merging #960 (d3dee69) into master (1437c9c) will not change coverage.
The diff coverage is 100.00%.

❗ Current head d3dee69 differs from pull request most recent head 62b0f11. Consider uploading reports for the commit 62b0f11 to get more accurate results

@@            Coverage Diff            @@
##            master      #960   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
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  Files          123       124    +1     
  Lines         2000      2025   +25     
  Branches       484       486    +2     
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+ Hits          2000      2025   +25     

Impacted Files	Coverage Δ
helpers/discordAuth.ts	100.00% <100.00%> (ø)