Add note on the readme about versions

Author: willdurand

README.md

@@ -7,6 +7,10 @@ Status](https://secure.travis-ci.org/geocoder-php/BazingaGeocoderBundle.png)](ht
 Integration of the [**Geocoder**](http://github.com/geocoder-php/Geocoder) library
 into Symfony2.
 
+**Important:** this bundle is developed in sync with [Geocoder's
+repository](http://github.com/geocoder-php/Geocoder). If you are using Geocoder
+`1.x`, you need to use the `~1.5` releases of the bundle (or lower).
+
 
 Documentation
 -------------
@@ -15,7 +19,8 @@ For documentation, see:
 
     Resources/doc/
 
-[Read the documentation](https://github.com/geocoder-php/BazingaGeocoderBundle/blob/master/Resources/doc/index.md)
+[Read the
+documentation](https://github.com/geocoder-php/BazingaGeocoderBundle/blob/master/Resources/doc/index.md)
 
 
 Contributing