anchor.diff:  
   ### Tip0 (object)
   + id: `51155739-1028-4479-a425-9ebaa501d9fe` (string, required) - Tip UUID, 36 chars, 8-4-4-4-12 chars
  -+ prompt: `First prompt` (string) - prompt attribute for Tip
  ++ essence: `First tip content` (string) - content of a Tip
  ++ difficult: `0` (int) - difficult level of a Tip, must be between 0 and 10
   
   ### Tip1 (object)
   + id: `6351db42-6597-42ba-909c-11488ee9814a` (string, required) - Tip UUID, 36 chars, 8-4-4-4-12 chars
  -+ prompt: `Second prompt` (string) - prompt attribute for Tip\
  ++ essence: `Second tip content` (string) - content of a Tip
  ++ difficult: `4` (int) - difficult level of a Tip, must be between 0 and 10
   
   ### Tip2 (object)
   + id: `e9b7760a-b645-4c35-9b4e-f5af5c1826c0` (string, required) - Tip UUID, 36 chars, 8-4-4-4-12 chars
  -+ prompt: `Third prompt` (string) - prompt attribute for Tip
  ++ essence: `Third tip content` (string) - content of a Tip
  ++ difficult: `9` (int) - difficult level of a Tip, must be between 0 and 10
   
   ### Tag0 (object)
   + id: `13972214-cf00-4239-aff6-eaad03f4b841` (string, required) - Tag UUID, 36 chars, 8-4-4-4-12 chars
  
positive.code: 
  # Change log
  
  ## 28/04/2016 toja
   - name of parameter isEnabled changed to flashcardsCount
  ## 17/04/2016 toja
  
negative.code: 
  ## BadRequestResponse (object)
  + code: `E001` (string, required) - TODO sample error code
  + message: `Id cannot be null` (string, required) - TODO sample error message - human readable
  