created item groups and link banners and their associations and fixed bugs with join tables

front-api/db/migrate/20150322043737_create_link_banners.rb

@@ -0,0 +1,25 @@
+class CreateLinkBanners < ActiveRecord::Migration
+  def change
+    create_table :link_banners do |t|
+      t.string :image_url
+      t.boolean :start_page
+      t.integer :section_id
+      t.integer :category_id
+      t.integer :sub_category_id
+      t.integer :item_id
+      t.boolean :thank_you_page
+      t.boolean :search_result_page
+      t.boolean :checkout_page
+      t.date :beginning
+      t.date :ending
+      t.boolean :footer
+      t.boolean :header
+      t.string :link_url
+
+      t.timestamps null: false
+    end
+
+    drop_table :special_offers
+
+  end
+end

front-api/db/migrate/20150322044941_create_item_groups.rb

@@ -0,0 +1,13 @@
+class CreateItemGroups < ActiveRecord::Migration
+  def change
+    create_table :item_groups do |t|
+      t.string :name
+      t.text :description
+      t.boolean :visible
+
+      t.timestamps null: false
+    end
+  end
+
+  create_join_table :item, :item_groups
+end