anchor.diff:  
   # Change log
   
  +## 28/04/2016 arka
  + - fixed tips to current state
   ## 28/04/2016 toja
    - name of parameter isEnabled changed to flashcardsCount
   ## 17/04/2016 toja
  
positive.code: 
  ## BadRequestResponse (object)
  + code: `E001` (string, required) - TODO sample error code
  + message: `Id cannot be null` (string, required) - TODO sample error message - human readable
negative.code: + deckId: `291acb97-6f50-4522-8049-aee0b4e16b42` (string, required) - Deck UUID, 36 chars, 8-4-4-4-12 chars
  
  ### TipWithoutId (object)
  + essence: `Sample content` (string) - content of a Tip
  + difficult: `8` (int) - difficult level of a Tip, must be between 0 and 10
  
  ### Tip (TipWithoutId)
  + id: `12345678-9012-3456-7890-123456789012` (string, required) - tip UUID, 36 chars, 8-4-4-4-12 chars
  