Remove replaces from squashed migrations

[FernandoKGA]

Description

This PR removes the replaces attribute from squashed migrations 0001-0005, resolving the issue where Django's migrate --prune command fails.

Fixes #899

Changes

Removed the replaces attribute from the following migration files:

• 0001_initial.py
• 0002_add_related_name.py
• 0003_alter_email_max_length.py
• 0004_auto_20160423_0400.py
• 0005_auto_20160727_2333.py

Motivation

These squashed migrations have been in place for several years and are already applied in all production databases. According to Django's migration documentation, once a squashed migration is deployed everywhere, the replaces attribute should be removed.

The presence of these attributes prevents users from running python manage.py migrate --prune, which is necessary for:

• Database migration cleanup
• Managing cross-app migration dependencies
• Performing migration reference updates in other apps

Impact

⚠️ Important Migration Requirements:

• For existing projects: You MUST have already applied the squashed migrations (0001-0005) before upgrading to this version. If you haven't run these migrations yet, do NOT upgrade.
• For new projects: No issues - you can use this version from the start.
• Breaking changes: Removes the ability to migrate from pre-squashed migration state. Projects that haven't yet applied migrations 0001-0005 should upgrade to a previous version first, run migrations, then upgrade to this version.
• Backwards compatibility: Fully maintained for projects with migrations already applied. The database schema remains unchanged.
• Benefits: Enables proper use of Django's migrate --prune command and other migration management operations.

Given that these squashed migrations were introduced several years ago, the vast majority of installations should already have them applied.

Testing

• Verified that python manage.py showmigrations correctly shows all migrations as applied
• Confirmed that python manage.py migrate --prune now runs without errors

Checklist

• Removed replaces attributes from squashed migrations
• No database schema changes
• Resolves the issue preventing migrate --prune usage

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.30%. Comparing base (3495aeb) to head (d92bfb2).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #900      +/-   ##
==========================================
- Coverage   93.33%   93.30%   -0.03%     
==========================================
  Files          42       42              
  Lines        1350     1345       -5     
  Branches       62       62              
==========================================
- Hits         1260     1255       -5     
  Misses         67       67              
  Partials       23       23              

Flag	Coverage Δ
unittests	93.30% <ø> (-0.03%)	⬇️

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[nijel]

Merged, thanks for your contribution!