Update README.md

Author: maxiloc

README.md

@@ -391,7 +391,7 @@ To clear an index, use the `clearIndices` class method:
 Contact::clearIndices();
 ```
 
-## Master/Slave
+## Manage indices
 
 ### Master/Slave
 
@@ -441,8 +441,6 @@ To search using a slave use the following code:
 Book::search('foo bar', ['index' => 'contacts_desc']);
 ```
 
-## Target Multiple Indexes
-
 ### Target Multiple Indexes
 
 You can index a record in several indexes using the <code>$indices</code> property: