Add logic to infer the base for Dyeworks items

This works for most of the current 1,094 Dyeworks items! But there are
a few exceptions, for cases where the base item name is not quite the
same (e.g. the Dyeworks version is more concise). Maybe we'll add a
database field to override this?

- Dyeworks Baby Blue: Baby Valentine Jumper
- Dyeworks Baby Pink: Baby Valentine Jumper
- Dyeworks Black: Field of Flowers
- Dyeworks Black: Games Master Challenge 2010 Lulu Shirt
- Dyeworks Blue: Field of Flowers
- Dyeworks Blue: Stars and Glitter Facepaint
- Dyeworks Brown: Hanging Winter Candles Garland
- Dyeworks Green: Stars and Glitter Facepaint
- Dyeworks Magenta: Lovely Berry Blush
- Dyeworks Orange & Pink: Winter Lights Effects
- Dyeworks Orange: Games Master Challenge 2010 Lulu Shirt
- Dyeworks Peach: Lovely Berry Blush
- Dyeworks Purple: Baby Valentine Jumper
- Dyeworks Purple: Games Master Challenge 2010 Lulu Shirt
- Dyeworks Purple: Hanging Winter Candles Garland
- Dyeworks Purple: Stars and Glitter Facepaint
- Dyeworks Red & Green: Winter Lights Effects
- Dyeworks Silver: Hanging Winter Candles Garland
- Dyeworks Soft Pink: Lovely Berry Blush
- Dyeworks Yellow & Magenta: Winter Lights Effects
- Dyeworks Yellow: Field of Flowers

app/models/item.rb

@@ -195,6 +195,26 @@ class Item < ApplicationRecord
     nc_mall_record.present?
   end
 
+  def dyeworks?
+    dyeworks_base_item.present?
+  end
+
+  DYEWORKS_NAME_PATTERN = %r{
+    ^(
+      # Most Dyeworks items have a colon in the name.
+      Dyeworks\s+(?<color>.+?:)\s*(?<base>.+)
+      |
+      # But sometimes they omit it. If so, assume the first word is the color!
+      Dyeworks\s+(?<color>\S+)\s*(?<base>.+)
+    )$
+  }x
+  def dyeworks_base_item
+    name_match = name.match(DYEWORKS_NAME_PATTERN)
+    return nil if name_match.nil?
+
+    Item.find_by_name(name_match["base"])
+  end
+
   def owned?
     @owned || false
   end