Add reference to endless-transaction

[jchapuis]

No description provided.

[what-the-diff]

PR Summary

• Created New Documentation File: transactions.md
  A new file named transactions.md has been introduced. This file contains comprehensive information about 'endless-transaction', a side library we're using. This library lets us perform operations across multiple entities in our system and helps to ensure data consistency. It also demonstrates how it seamlessly integrates with our existing platforms and provides an illustrative example for better understanding.

• Updated index.md with Link to New File
  The index.md file has been updated to include a link to our newly added transactions.md file for easier navigation. This promotes ease of access to the new documentation from within the existing index.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.61%. Comparing base (aa1ba0f) to head (0fb2b0c).
Report is 8 commits behind head on master.

❗ Current head 0fb2b0c differs from pull request most recent head 47b1f50. Consider uploading reports for the commit 47b1f50 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #315      +/-   ##
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- Coverage   89.73%   89.61%   -0.12%     
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  Files          73       73              
  Lines         877      867      -10     
  Branches       94       98       +4     
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- Hits          787      777      -10     
  Misses         90       90