Linted code iwht black tool

src/migrations/add_category_history.py

@@ -17,20 +17,20 @@ from models import Base, CategoryHistory
 def migrate():
     """Create CategoryHistory table if it doesn't exist."""
     print("Starting migration: Adding CategoryHistory table...")
-    
+
     try:
         db = get_database()
-        
+
         # Initialize database if not already done
         if not db._initialized:
             db.initialize()
-        
+
         # Create only the CategoryHistory table
         CategoryHistory.__table__.create(db._engine, checkfirst=True)
-        
+
         print("✓ Migration completed successfully!")
         print("  - CategoryHistory table created")
-        
+
     except Exception as e:
         print(f"✗ Migration failed: {e}")
         sys.exit(1)