title: Sequelize hook afterUpdate How to get dirty fields, original value and updated value?
body: <p>I'm stuck with sequelize hooks, trying to write every change to a model into a log table. Therefore I'm looking for a way to access the models data before and after the write to MySQL. </p>
  
  <p>How can I access this data within Sequelize Hook afterUpdate?</p>
  
  <p>How can I get the updated/changed/dirty fields? </p>
  
  <p>How can I access data before and after the update to make diffs?</p>