Add initial Docker and Alembic setup

Introduce a `docker-compose.yml` to define the services for backend and database with health checks. Add Alembic configurations for database migrations and an initial empty migration. Include backend-related Docker setup with an entrypoint script for database migration execution.

backend/entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -e
+echo "Starting Backend"
+
+# Apply database migrations
+alembic upgrade head
+# Execute the command passed to docker run
+exec "$@"