fix docs

README.md

@@ -1,3 +1,5 @@
+<p align="center"><img src="resources/images/stamp.jpg?raw=true"></p>
+
 # Laravel Stampable
 
 [![Software License][ico-license]](LICENSE.md)
@@ -30,6 +32,8 @@ Via Composer
 $ composer require shetabit/stampable
 ```
 
+# How to use
+
 ## Configure Migration
 
 In your migration you must add `timestamp` field per each stamp.
@@ -85,7 +89,9 @@ class Category extends Model implements Stampable
 }
 ```
 
-stamps must be in ['stampName' => 'databaseFieldName'] format.
+stamps must be in `['stampName' => 'databaseFieldName']` format.
+
+## Working with stamps
 
 Model creates methods and local scopes for each stamp dynamically.