Update README file to show the correct way of using maxmind_local lookup.

README.md

@@ -430,7 +430,7 @@ Yahoo BOSS is **not a free service**. As of November 17, 2012 Yahoo no longer of
 * **Documentation**: http://www.maxmind.com/en/city
 * **Terms of Service**: ?
 * **Limitations**: ?
-* **Notes**: You must add the **geoip gem** to your Gemfile or have it installed in your system. You also have to specify the path of the MaxMind database in your configuration. For example: `Geocoder.configure(:maxmind_local => {:database => File.join('folder', 'GeoLiteCity.dat')})`.
+* **Notes**: You must add the **geoip gem** to your Gemfile or have it installed in your system. You also have to specify the path of the MaxMind database in your configuration. For example: `Geocoder.configure(ip_lookup: :maxmind_local, :maxmind_local => {:database => File.join('folder', 'GeoLiteCity.dat')})`.
 
 #### ESRI (`:esri`)