If you want to get cracking on the JavaScript source then do this:

    git clone git@github.com:guyroyse/gilded-rose-javascript.git

Hi and welcome to team Gilded Rose.

As you know, we are a small inn with a prime location in a prominent city ran
by a friendly innkeeper named Allison.  We also buy and sell only the finest
goods. Unfortunately, our goods are constantly degrading in quality as they
approach their sell by date.

We have a system in place that updates our inventory for us. It was developed
by a no-nonsense type named Leeroy, who has moved on to new adventures. Your
task is to add the new feature to our system so that we can begin selling a
new category of items.

First an introduction to our system:

  - All items have a *sell_in* 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

Pretty simple, right? Well this is where it gets interesting:

  - Once the *sell_in* days is less then zero, *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 nor does it
    decrease in *quality*

  - "Backstage passes", like aged brie, increases in *quality* as it's *sell_in*
    value decreases; *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

We have recently signed a supplier of conjured items. This requires an update
to our system:

  - "Conjured" items degrade in *quality* twice as fast as normal items

Feel free to make any changes to the *update_quality* method and add any new
code as long as everything still works correctly. However, do not alter the
*Item* class or *items* property as those belong to the goblin in the corner
who will insta-rage and one-shot you as he doesn't believe in shared code
ownership.

Just for clarification, 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.

Sources:
  <http://www.iamnotmyself.com/2011/02/13/RefactorThisTheGildedRoseKata.aspx>
  <https://github.com/professor/GildedRose>