#590 Add explanation to Decorator pattern

decorator/etc/decorator.urm.puml

@@ -1,38 +0,0 @@
-@startuml
-package com.iluwatar.decorator {
-  class App {
-    - LOGGER : Logger {static}
-    + App()
-    + main(args : String[]) {static}
-  }
-  class ClubbedTroll {
-    - LOGGER : Logger {static}
-    + ClubbedTroll(decorated : Troll)
-    + attack()
-    + getAttackPower() : int
-  }
-  class SimpleTroll {
-    - LOGGER : Logger {static}
-    + SimpleTroll()
-    + attack()
-    + fleeBattle()
-    + getAttackPower() : int
-  }
-  interface Troll {
-    + attack() {abstract}
-    + fleeBattle() {abstract}
-    + getAttackPower() : int {abstract}
-  }
-  class TrollDecorator {
-    - decorated : Troll
-    + TrollDecorator(decorated : Troll)
-    + attack()
-    + fleeBattle()
-    + getAttackPower() : int
-  }
-}
-TrollDecorator -->  "-decorated" Troll
-ClubbedTroll --|> TrollDecorator 
-SimpleTroll ..|> Troll 
-TrollDecorator ..|> Troll 
-@enduml