README.md in PageRankr-1.6.0 vs README.md in PageRankr-1.7.0

@@ -35,10 +35,32 @@
 You can also use the alias `backlink` instead of `backlinks`.
 Valid search engines are: `:google, :bing, :yahoo, :altavista, :alltheweb, :alexa`. To get this list you can do:
 
     PageRankr.backlink_trackers #=> [:alexa, :alltheweb, :altavista, :bing, :google, :yahoo]
 
+### Indexes
+
+Indexes are the result of doing a search with a query like "site:www.google.com". The number of returned results indicates how many pages of a domain are indexed by a particular search engine.
+
+    PageRankr.indexes('www.google.com', :google)       #=> {:google=>4860000}
+    PageRankr.indexes('www.google.com', :bing)         #=> {:bing=>2120000}
+
+If you don't specify a search engine, then all of them are used.
+
+    # this
+    PageRankr.indexes('www.google.com')
+        #=> {:bing=>2120000, :google=>4860000}
+
+    # is equivalent to
+    PageRankr.indexes('www.google.com', :google, :bing)
+        #=> {:bing=>2120000, :google=>4860000}
+
+You can also use the alias `index` instead of `indexes`.
+Valid search engines are: `:google, :bing`. To get this list you can do:
+
+    PageRankr.index_trackers #=> [:alexa, :alltheweb, :altavista, :bing, :google, :yahoo]
+
 ### Ranks
 
     PageRankr.ranks('www.google.com', :alexa, :google) #=> {:alexa=>{:us=>1, :global=>1}, :google=>10}
 
     # this also gives the same result
@@ -55,11 +77,11 @@
 ## Fix it!
 
 If you ever find something is broken it should now be much easier to fix it with version >= 1.3.0. For example, if the xpath used to lookup a backlink is broken, just override the method for that class to provide the correct xpath.
 
     module PageRankr
-      class Backlinks
+      class Backlinks < Tracker
         class Google < Backlink
           def xpath
             "my new awesome xpath"
           end
         end
@@ -69,11 +91,11 @@
 ## Extend it!
 
 If you ever come across a site that provides a rank or backlinks you can hook that class up to automatically be use with PageRankr.
 
     module PageRankr
-      class Backlinks
+      class Backlinks < Tracker
         class Foo < Backlink
           def url(site)
             "http://example.com/?q=#{site}"
           end
 
@@ -103,12 +125,10 @@
 
 ## TODO Version 2
 * Use API's where possible
 * Use [Typhoeus](https://github.com/pauldix/typhoeus) to improve speed when requesting multiple ranks and/or backlinks
 * Configuration
-    * API keys
-    * Alexa rank options
-* Add compete rank tracker
+    * Optionally use API keys
 
 ## Contributors
 * [Druwerd](http://github.com/Druwerd) - Use Google Search API instead of scraping.
 
 ## Shout Out
\ No newline at end of file