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