feat: Alembic setup, User and AuditLog models with migration

Co-Authored-By: Claude <noreply@anthropic.com>

backend/alembic/env.py

@@ -0,0 +1,46 @@
+from logging.config import fileConfig
+
+from alembic import context
+
+from app.config import settings
+from app.database import Base
+from app.models import *  # noqa: F401,F403
+
+config = context.config
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+target_metadata = Base.metadata
+
+
+def run_migrations_offline():
+    url = settings.database_url
+    context.configure(url=url, target_metadata=target_metadata, literal_binds=True)
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection):
+    context.configure(connection=connection, target_metadata=target_metadata)
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations():
+    from app.database import engine
+
+    async with engine.begin() as conn:
+        await conn.run_sync(do_run_migrations)
+
+
+def run_migrations_online():
+    import asyncio
+
+    asyncio.run(run_async_migrations())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()