Add model for unix uid

[SaranjeetKaur]

Description

This pull request introduces a new model called UnixUID to the imperial_coldfront_plugin application. The UnixUID model is designed to map a user to a unique identifier. The changes include the creation of a migration file and the addition of the new model to the existing models file.

Fixes #32

Type of change

• Documentation (non-breaking change that adds or improves the documentation)
• New feature (non-breaking change which adds functionality)
• Optimization (non-breaking, back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (whatever its nature)

Key checklist

• All tests pass (eg. python -m pytest)
• The documentation builds and looks OK (eg. python -m sphinx -b html docs docs/build)
• Pre-commit hooks run successfully (eg. pre-commit run --all-files)

Further checks

• Code is commented, particularly in hard-to-understand areas
• Tests added or an issue has been opened to tackle that in the future. (Indicate issue here: # (issue))

[SaranjeetKaur]

The steps that I have followed so far:

• Added the UnixUID model to models.py
• Then run python makemigrations.py (since, here it is equivalent to python manage.py makemigrations)
• Then run pre-commit run --all-files to make sure all checks pass
• All ok when running pytest too

Questions:

1. The Django tutorial mentions 3 steps for making model changes:

   • Change your models (in models.py).
   • Run python manage.py makemigrations to create migrations for those changes.
   • Run python manage.py migrate to apply those changes to the database.

   I am not sure how to run the third step in the absence of a manage.py file

2. How to deploy and view the changes to the app?

[cc-a]

Very nice. Just a couple of small tweaks.