Add genre class

genre.rb

@@ -0,0 +1,22 @@
+require_relative 'item'
+
+class Genre
+  attr_accessor :name
+
+  def initialize(name, id = nil)
+    @id = id || Random.rand(1..1000)
+    @name = name
+    @items = []
+  end
+
+  def add_item(item)
+    return unless item.is_a?(Item)
+
+    @items << item
+    item.genre = self
+  end
+
+  private
+
+  attr_accessor :id, :items
+end