anchor.diff:  ```
     </div>
     <div data-tab="Ruby SDK" data-lang="ruby">
  -(TODO: UPDATE ME)
  +
   ```ruby
   # Create a client object.
   client = PredictionIO::EventClient.new(<ACCESS KEY>, <URL OF EVENTSERVER>)
   
  -# A user rates an item.
  -client.create_event(
  -  'rate',
  +# Create a new user
  +client.create_event(
  +  '$set',
     'user',
  -  <USER ID>, {
  -    'targetEntityType' => 'item',
  -    'targetEntityId' => <ITEM ID>,
  -    'properties' => { 'rating' => <RATING (float)> }
  +  <USER ID>
  +)
  +
  +# Create a new item or set existing item's categories
  +client.create_event(
  +  '$set',
  +  'item',
  +  <ITEM ID>, {
  +    'properties' => { 'categories' => ['<CATEGORY_1>', '<CATEGORY_2>'] }
     }
   )
   
  -# A user buys an item.
  -client.create_event(
  -  'buy',
  +# A user views an item.
  +client.create_event(
  +  'view',
     'user',
     <USER ID>, {
       'targetEntityType' => 'item',
       'targetEntityId' => <ITEM ID>
     }
   )
  +
   ```
     </div>
     <div data-tab="Java SDK" data-lang="java">
  -(TODO: UPDATE ME)
  +
   ```java
   import io.prediction.Event;
   import io.prediction.EventClient;
   
  +import com.google.common.collect.ImmutableList;
  +
   EventClient client = new EventClient(<ACCESS KEY>, <URL OF EVENTSERVER>);
   
  -// A user rates an item
  -Event rateEvent = new Event()
  -    .event("rate")
  -    .entityType("user")
  -    .entityId(<USER_ID>)
  -    .targetEntityType("item")
  -    .targetEntityId(<ITEM_ID>)
  -    .property("rating", new Float(<RATING>));
  -client.createEvent(rateEvent);
  -
  -// A user buys an item
  -Event buyEvent = new Event()
  -    .event("buy")
  +// Create a new user
  +Event userEvent = new Event()
  +  .event("$set")
  +  .entityType("user")
  +  .entityId(<USER_ID>);
  +client.createEvent(userEvent);
  +
  +// Create a new item or set existing item's categories
  +Event itemEvent = new Event()
  +  .event("$set")
  +  .entityType("item")
  +  .entityId(<ITEM_ID>)
  +  .property("categories", ImmutableList.of("<CATEGORY_1>", "<CATEGORY_2>"));
  +client.createEvent(itemEvent)
  +
  +// A user views an item
  +Event viewEvent = new Event()
  +    .event("view")
       .entityType("user")
       .entityId(<USER_ID>)
       .targetEntityType("item")
       .targetEntityId(<ITEM_ID>);
  -client.createEvent(buyEvent);
  +client.createEvent(viewEvent);
  +
   ```
     </div>
     <div data-tab="REST API" data-lang="json">
  
positive.code: ```
    </div>
    <div data-tab="PHP SDK" data-lang="php">
  (TODO: UPDATE ME)
  ```php
  <?php
  require_once("vendor/autoload.php");
  
negative.code: 
  $client = new EventClient(<ACCESS KEY>, <URL OF EVENTSERVER>);
  
  // Create a new user
  $client->createEvent(array(
    'event' => '$set',
    'entityType' => 'user',
    'entityId' => <USER ID>
  ));
  
  // Create a new item or set existing item's categories
  $client->createEvent(array(
    'event' => '$set',
    'entityType' => 'item',
    'entityId' => <ITEM ID>
    'properties' => array('categories' => array('<CATEGORY_1>', '<CATEGORY_2>'))
  ));
  
  // A user views an item
  $client->createEvent(array(
     'event' => 'view',
     'entityType' => 'user',
     'entityId' => <USER ID>,
     'targetEntityType' => 'item',
  