title: Sequelize update ignores invalid column names
body: <p>When I try to update a certain entry in the db, sequelize - Model.update() ignores the wrong column name passed to it. Say my table has columns 'id' and 'password', if I pass an object that has 'id' and 'pwd' to the update function, the 'pwd' is simply ignored and 'id' is updated.</p>
  
  <p>Is there a way, through sequelize, to check if an invalid column name is being passed to the update function?  </p>