## Why refactoring ?
- Ability to easily add new kind of items(like conjured) 
- However, without altering the Item class or Items property
                                                        
## Requirements

- All items have a SellIn value which denotes the number of days we have to sell the item
- All items have a Quality value which denotes how valuable the item is
- At the end of each day our system lowers both values for every item

# unit tests
-[x] At the end of each day our system lowers both values for every item
-[x] Once the sell by date has passed, Quality degrades twice as fast
-[ ] The Quality of an item is never negative
-[ ] "Aged Brie" actually increases in Quality the older it gets
-[ ] The Quality of an item is never more than 50
-[ ] "Sulfuras", being a legendary item, never has to be sold or decreases in Quality
-[ ] "Backstage passes", like aged brie, increases in Quality as its SellIn value approaches;
-[ ] Quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less but
-[ ] Quality drops to 0 after the concert
-[ ] an item can never have its Quality increase above 50, however "Sulfuras" is a legendary item and as such its Quality is 80 and it never alters.

## Technical Issues, with a balanced priority
-[ ]

## Refactoring actions