anchor.diff:     'entityId' => <USER ID>,
      'targetEntityType' => 'item',
      'targetEntityId' => <ITEM ID>,
  -   'properties' => array('ratings'=> <RATING>)
  +   'properties' => array('rating'=> <RATING>)
   ));
   
   // A user buys an item
  
positive.code: 
  ## Create a new Engine from an Engine Template
  
  Now let's create a new engine called *MyRecommendation* by cloning the Recommendation 
  Engine Template, assuming `/home/yourname/predictionio`
  is the installation directory of PredictionIO:
  
  
negative.code:   "targetEntityType" : "item",
    "targetEntityId" : <ITEM ID>,
    "properties" : {
      "rating" : <RATING>
    }
    "eventTime" : <TIME OF THIS EVENT>
  }'
  