README: Add ruby gem to related projects

[abeidahmed]

• Add the ruby gem to related projects on README.md

[codecov]

Codecov Report

Merging #1060 (9f5cd0b) into master (a718a7e) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master     #1060   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            5         5           
  Lines           34        34           
  Branches         3         3           
=========================================
  Hits            34        34           

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