AAI-119 set up migrations for aai-backend database

[marius-mather]

Description

AAI-119: set up ways to generate migrations (using a local postgres instance) and ensure we can run them against the deployed service.

Changes

• Create a generate_migrations.py script to generate migrations against a postgres instance
• Update CDK deployment to allow command execution for migrations
• Generate initial migrations

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have added unit / integration tests that prove my fix is effective or that my feature works
• I have run all tests locally and they pass
• I have updated the documentation (if applicable)

How to Test Manually (if necessary)

Run uv run python generate_migrations.py --check to check that alembic is happy with the state of the migrations.

[amandazhuyilan]

Ran uv run python generate_migrations.py --check locally with this branch and seems that everyone has to be happy:

🚀 Starting temporary Postgres container...
> docker run --rm -d --name temp_alembic_db -e POSTGRES_USER=testuser -e POSTGRES_PASSWORD=testpass -p 5433:5432 postgres:17
cb158ede614f9d26c93c0e56c1d456e8249dfc8a3c7d09464a4cdbc18abe9d52
⏳ Waiting for database to be ready...
🧱 Applying existing Alembic migrations...
> alembic upgrade head
INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO  [alembic.runtime.migration] Will assume transactional DDL.
INFO  [alembic.runtime.migration] Running upgrade  -> 101f45395233, add_group_membership
🔍 Running 'alembic check'...
> alembic check
INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO  [alembic.runtime.migration] Will assume transactional DDL.
No new upgrade operations detected.
🧹 Cleaning up: stopping container...
temp_alembic_db

Had to restart my docker on mac first ;)

[amandazhuyilan]

Looks good to me - thanks for making the change