Added info about Header modifiers

README.md

@@ -47,6 +47,16 @@ OkHttpClient okHttp = new OkHttpClient.Builder()
 
 To get know more about Interceptor in OkHttp take a look here: https://github.com/square/okhttp/wiki/Interceptors
 
+## Header modifiers
+Ok2Curl allows you to modify any header before creating curl command. All you have to do is create your own modifier that implements [HeaderModifier](https://github.com/mrmike/Ok2Curl/blob/master/ok2curl/src/main/java/com/moczul/ok2curl/modifier/HeaderModifier.java) 
+and add this modifier to CurlInterceptor. See [sample](https://github.com/mrmike/Ok2Curl/blob/master/sample/src/main/java/com/moczul/sample/RequestService.java) for reference.
+```
+        final BasicAuthorizationHeaderModifier modifier = new BasicAuthorizationHeaderModifier(new Base64Decoder());
+        final List<HeaderModifier> modifiers = Collections.<HeaderModifier>singletonList(modifier);
+
+        final CurlInterceptor curlInterceptor = new CurlInterceptor(new AndroidLogger(), modifiers);
+```
+
 ## License
 
     Copyright 2015 Michał Moczulski