Add alembic DB schema management (#86)

* Use alembic
* add creation helper
* example migration tool

create_migration.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+"""
+Helper script to create Alembic migrations from SQLAlchemy model changes.
+
+Usage:
+    ./env/bin/python create_migration.py
+
+This will:
+1. Load your current models from meshview/models.py
+2. Compare them to the current database schema
+3. Auto-generate a migration with the detected changes
+4. Save the migration to alembic/versions/
+
+After running this, review the generated migration file before committing!
+"""
+
+import os
+import sys
+
+# Add current directory to path
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+
+from alembic.config import Config
+
+from alembic import command
+
+# Create Alembic config
+alembic_cfg = Config("alembic.ini")
+
+# Set database URL from meshview config
+try:
+    from meshview.config import CONFIG
+
+    database_url = CONFIG["database"]["connection_string"]
+    alembic_cfg.set_main_option("sqlalchemy.url", database_url)
+    print(f"Using database URL from config: {database_url}")
+except Exception as e:
+    print(f"Warning: Could not load meshview config: {e}")
+    print("Using default database URL")
+    alembic_cfg.set_main_option("sqlalchemy.url", "sqlite+aiosqlite:///packets.db")
+
+# Generate migration
+try:
+    print("\nComparing models to current database schema...")
+    print("Generating migration...\n")
+    command.revision(alembic_cfg, autogenerate=True, message="Auto-generated migration")
+    print("\n✓ Successfully created migration!")
+    print("\nNext steps:")
+    print("1. Review the generated file in alembic/versions/")
+    print("2. Edit the migration message/logic if needed")
+    print("3. Test the migration: ./env/bin/alembic upgrade head")
+    print("4. Commit the migration file to version control")
+except Exception as e:
+    print(f"\n✗ Error creating migration: {e}")
+    import traceback
+
+    traceback.print_exc()
+    sys.exit(1)