sales and orders methods updates

db/migrate/20170403135121_create_customers.rb

@@ -5,6 +5,7 @@ class CreateCustomers < ActiveRecord::Migration[5.0]
       t.string :company
       t.string :contact_no
       t.string :email
+      t.date   :date_of_birth
       t.string :membership_id
       t.string :membership_type
       t.string :membership_authentication_code

db/migrate/20170408105938_create_seed_generators.rb

@@ -0,0 +1,12 @@
+class CreateSeedGenerators < ActiveRecord::Migration[5.0]
+  def change
+    create_table :seed_generators do |t|
+      t.string :model, :null => false, :default => "sale"
+      t.integer :increase_by, :null => false, :default => 1
+      t.bigint :current, :null => false ,:default => 1
+      t.bigint :next, :null => false, :default => 2
+
+      t.timestamps
+    end
+  end
+end