Adds a .gitignore file.
Introduces the ItemInventory class that adapts instances of the Item class.
Duplicates the methods that manipulate item quality into ItemInventory and delegates to them.
Inlines the delegating methods.
Duplicates the method that manipulates item sell_in into ItemInventory and delegates to them.
Inlines the delegating method.
Adds the rollover method to fully encapsulate the Item delegate.
Adds the delta parameter to the #decrease_quality and #increase_quality methods.
Uses the delta parameter to simplify.
Corrects the guard behaviour for the #decrease_quality and #increase_quality methods; Adds a spec for InventoryItem.
Uses a case with a range to simplify the quality increases for backstage passes.
Merge branch 'introduce_item_inventory_adaptor'