Documentation-related changes

[dbarkowsky]

🎯 Summary

Two changes to facilitate the wiki documentation:

• Adding the file that describes the diagram from dbdiagram.io
• Fixing an if statement in the migrations script

🔰 Checklist

• I have read and agree with the following checklist and am following the guidelines in our Code of Conduct document.

• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation where required.
• I have tested my changes to the best of my ability.
• My changes generate no new warnings.

[github-actions]

🚀 Deployment Information

The Express API Image has been built with the tag: 2694. Please make sure to utilize this specific tag when promoting these changes to the TEST and PROD environments during the API deployment. For more updates please monitor Image Tags Page on Wiki.

[codeclimate]

Code Climate has analyzed commit 8d3dd04 and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 93.0%.

View more on Code Climate.