delay migrator loading

lib/sequelize.js

@@ -2,7 +2,6 @@ var Utils             = require("./utils")
   , DAOFactory        = require("./dao-factory")
   , DataTypes         = require('./data-types')
   , DAOFactoryManager = require("./dao-factory-manager")
-  , Migrator          = require("./migrator")
   , QueryInterface    = require("./query-interface")
 
 if (typeof process != 'undefined' && parseFloat(process.version.replace('v', '')) < 0.6) {
@@ -85,6 +84,7 @@ module.exports = (function() {
   }
 
   Sequelize.prototype.getMigrator = function(options, force) {
+    var Migrator = require("./migrator")
     if (force) {
       this.migrator = new Migrator(this, options)
     } else {