README.md in couchbase-orm-0.2.0 vs README.md in couchbase-orm-0.2.1

@@ -99,19 +99,42 @@
 
       # Generates two functions:
       # * the by_author view above
       # * def find_by_author(author); end
       index_view :author
+      
+      # You can make compound keys by passing an array to :emit_key
+      # this allow to query by read/unread comments
+      view :by_read, emit_key: [:user_id, :read]
+      # this allow to query by view_count
+      view :by_view_count, emit_key: [:user_id, :view_count]
+       
+      
+      
 
       validates_presence_of :author, :body
     end
 ```
 
 You can use `Comment.find_by_author('name')` to obtain all the comments by
 a particular author. The same thing, using the view directly would be:
 `Comment.by_author(key: 'name')`
 
+When using a compound key, the usage is the same, you just give the full key : 
+
+```ruby
+   Comment.by_read(key: '["'+user_id+'",false]') # gives all unread comments for one particular user
+   
+   # or even a range !
+   
+   Comment.by_view_count(startkey: '["'+user_id+'",10]', endkey: '["'+user_id+'",20]') # gives all comments that have been seen more than 10 times but less than 20
+```
+
+Check this couchbase help page to learn more on what's possible with compound keys : https://developer.couchbase.com/documentation/server/3.x/admin/Views/views-translateSQL.html
+
+Ex : Compound keys allows to decide the order of the results, and you can reverse it by passing `descending: true`
+
 ## Associations and Indexes
 
 There are common active record helpers available for use `belongs_to` and `has_many`
 
 ```ruby
@@ -127,5 +150,24 @@
         ensure_unique :email
     end
 ```
 
 
+## Performance Comparison with Couchbase-Ruby-Model
+
+Basically we migrated an application from [Couchbase Ruby Model](https://github.com/couchbase/couchbase-ruby-model)
+to [Couchbase-ORM](https://github.com/acaprojects/couchbase-orm) (this project)
+
+* Rails 5 production
+* Puma as the webserver
+* Running on a 2015 Macbook Pro
+* Performance test: `siege -c250 -r10  http://localhost:3000/auth/authority`
+
+The request above pulls the same database document each time and returns it. A simple O(1) operation.
+
+| Stat | Couchbase Ruby Model | Couchbase-ORM |
+| :--- | :---                 |   :---        |
+|Transactions|2500 hits|2500 hits|
+|Elapsed time|12.24 secs|8.20 secs|
+|Response time|0.88 secs|0.47 secs|
+|Transaction rate|204.25 trans/sec|304.88 trans/sec|
+|Request Code|[ruby-model-app](https://github.com/QuayPay/coauth/blob/95bbf5e5c3b3340e5af2da494b90c91c5e3d6eaa/app/controllers/auth/authorities_controller.rb#L6)|[couch-orm-app](https://github.com/QuayPay/coauth/blob/87f6fdeaab784ba252a5d38bbcf9e6b0477bb504/app/controllers/auth/authorities_controller.rb#L8)|