Nested isn't working, another approach, add trans validations

User a transactions border, select the customer from a view of users and customers

db/migrate/20121205043759_create_transactions.rb

@@ -2,8 +2,8 @@ class CreateTransactions < ActiveRecord::Migration
   def change
     create_table :transactions do |t|
       t.integer "vendor_id", :null => false
-      t.integer "customer_id"
-      t.integer "customer_type"
+      t.integer "customer_id", :null => false
+      t.integer "customer_type", :null => false
       t.integer "bike_id"
       t.integer "amount", :null => false
       t.string  "item", :null => false