anchor.diff:  be used. The mangoo I/O framework will automatically determine and use
   the strongest key possible.
   
  -=== Flash
  +== Flash
   
   Specially when working with forms it is useful to pass certain
   informations (e.g. error- or success messages) to the next request. To
  
positive.code: The prefix follows the field type (email, required, match, etc.) for the
  message.
  
  ==== CSRF Protection
  
  mangoo I/O allows you to retrieve an authenticity token for protection
  against https://de.wikipedia.org/wiki/Cross-Site-Request-Forgery[CSRF].
  
negative.code: the documentation on <<Form handling>> for more information on how to customize
  the specific error messages.
  
  == Form handling
  
  To access a form submitted to a controller class, you can simply pass
  the mangoo I/O Form class. Here is an example of how this might look
  