feat: cascade deleting price rangecs

models/service.py

@@ -19,8 +19,11 @@ class Service(BaseModel):
                           nullable=False,
                           comment='Тип услуги')
 
-    price_ranges = relationship('ServicePriceRange', back_populates='service', lazy='selectin',
+    price_ranges = relationship('ServicePriceRange',
-                                order_by="asc(ServicePriceRange.from_quantity)")
+                                back_populates='service',
+                                lazy='selectin',
+                                order_by="asc(ServicePriceRange.from_quantity)",
+                                cascade="all, delete-orphan")
 
 
 class ServicePriceRange(BaseModel):