Add initial VariantOverride model with price lookup

app/models/variant_override.rb

@@ -0,0 +1,8 @@
+class VariantOverride < ActiveRecord::Base
+  belongs_to :variant, class_name: 'Spree::Variant'
+  belongs_to :hub, class_name: 'Enterprise'
+
+  def self.price_for(variant, hub)
+    VariantOverride.where(variant_id: variant, hub_id: hub).first.andand.price
+  end
+end

db/migrate/20141113053004_create_variant_overrides.rb

@@ -0,0 +1,15 @@
+class CreateVariantOverrides < ActiveRecord::Migration
+  def change
+    create_table :variant_overrides do |t|
+      t.references :variant
+      t.references :hub
+      t.decimal :price, precision: 8, scale: 2
+      t.integer :count_on_hand
+    end
+
+    add_foreign_key :variant_overrides, :spree_variants, column: :variant_id
+    add_foreign_key :variant_overrides, :enterprises, column: :hub_id
+
+    add_index :variant_overrides, [:variant_id, :hub_id]
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20141023050324) do
+ActiveRecord::Schema.define(:version => 20141113053004) do
 
   create_table "adjustment_metadata", :force => true do |t|
     t.integer "adjustment_id"
@@ -1033,6 +1033,15 @@ ActiveRecord::Schema.define(:version => 20141023050324) do
     t.integer "state_id"
   end
 
+  create_table "variant_overrides", :force => true do |t|
+    t.integer "variant_id"
+    t.integer "hub_id"
+    t.decimal "price",         :precision => 8, :scale => 2
+    t.integer "count_on_hand"
+  end
+
+  add_index "variant_overrides", ["variant_id", "hub_id"], :name => "index_variant_overrides_on_variant_id_and_hub_id"
+
   add_foreign_key "adjustment_metadata", "enterprises", name: "adjustment_metadata_enterprise_id_fk"
   add_foreign_key "adjustment_metadata", "spree_adjustments", name: "adjustment_metadata_adjustment_id_fk", column: "adjustment_id"
 
@@ -1190,4 +1199,7 @@ ActiveRecord::Schema.define(:version => 20141023050324) do
 
   add_foreign_key "suburbs", "spree_states", name: "suburbs_state_id_fk", column: "state_id"
 
+  add_foreign_key "variant_overrides", "enterprises", name: "variant_overrides_hub_id_fk", column: "hub_id"
+  add_foreign_key "variant_overrides", "spree_variants", name: "variant_overrides_variant_id_fk", column: "variant_id"
+
 end

spec/models/variant_override_spec.rb

@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe VariantOverride do
+  describe "looking up prices" do
+    let(:variant) { create(:variant) }
+    let(:hub)     { create(:distributor_enterprise) }
+
+    it "returns the numeric price when present" do
+      VariantOverride.create!(variant: variant, hub: hub, price: 12.34)
+      VariantOverride.price_for(variant, hub).should == 12.34
+    end
+
+    it "returns nil otherwise" do
+      VariantOverride.price_for(variant, hub).should be_nil
+    end
+  end
+end