Fix papertrail integration

[jamesmacwilliam]

• Add option to call after_update hooks when transitioning state.
• Papertrail uses the after upate hook of a model, this ensures that the update hooks are called when changing state.
• uses:

workflow do
  with_callbacks
    # other important directives
  end

when with_callbacks is used in the workflow specification, ActiveRecord update callbacks will be invoked when transitioning state