use assocName and backAssocName for key generation of n-to-m assocs

lib/sequelize/SequelizeTable.js

@@ -51,8 +51,8 @@ exports.SequelizeTable = function(Sequelize, sequelize, tableName, attributes, o
             if(association.backAssociationName) {
               // many to many relation
               var _attributes = {}
-              _attributes[table.identifier] = Sequelize.INTEGER
-              _attributes[association.table.identifier] = Sequelize.INTEGER
+              _attributes[Sequelize.Helper.SQL.asTableIdentifier(association.name)] = Sequelize.INTEGER
+              _attributes[Sequelize.Helper.SQL.asTableIdentifier(association.backAssociationName)] = Sequelize.INTEGER
               sequelize.define(Sequelize.Helper.SQL.manyToManyTableName(association.name, association.backAssociationName), _attributes)
             } else {
               // one to many relation