items are functional for now

app/models/item.rb

@@ -1,6 +1,7 @@
 class Item < ActiveRecord::Base
   belongs_to :unit
   has_many :multi_media_descriptions
+  belongs_to :sub_category
 
-  validates_presence_of :name, :description, :list_price, :current_input_price, :tags, :unit_id, :code
+  validates_presence_of :name, :description, :list_price, :current_input_price, :tags, :unit_id, :code, :sub_category_id
 end

app/models/multi_media_description.rb

@@ -1,5 +1,4 @@
 class MultiMediaDescription < ActiveRecord::Base
   belongs_to :item
   belongs_to :media_type
-
 end

app/models/sub_category.rb

@@ -1,3 +1,5 @@
 class SubCategory < ActiveRecord::Base
   belongs_to :category
+  has_many :items
+  belongs_to :sub_category
 end