Update IoC and DI demos

examples/ioc_di_demos/car_engine.py

@@ -10,7 +10,7 @@ class Car(object):
 
     def __init__(self):
         """Initializer."""
-        self.engine = Engine()
+        self.engine = Engine()  # Engine is a "hardcoded" dependency
 
 
 if __name__ == '__main__':

examples/ioc_di_demos/car_engine_ioc.py

@@ -10,7 +10,7 @@ class Car(object):
 
     def __init__(self, engine):
         """Initializer."""
-        self.engine = engine
+        self.engine = engine  # Engine is an "injected" dependency
 
 
 if __name__ == '__main__':

examples/ioc_di_demos/car_engine_ioc_container.py

@@ -1,14 +1,14 @@
 """Example of inversion of control container for Car & Engine example."""
 
-from dependency_injector import catalogs
+from dependency_injector import containers
 from dependency_injector import providers
 
 from car_engine_ioc import Car
 from car_engine_ioc import Engine
 
 
-class Components(catalogs.DeclarativeCatalog):
-    """Catalog of component providers."""
+class Components(containers.DeclarativeContainer):
+    """IoC container of component providers."""
 
     engine = providers.Factory(Engine)