Updated README to include a small note on the posibility to generate …

…lang files pero available languages automatically

README.rdoc

@@ -50,6 +50,14 @@ If <tt>only</tt> is omitted all the translations will be saved. Also, make sure
   - file: 'public/javascripts/pt-BR.js'
     only: 'pt-BR.*'
 
+Optionaly, you can auto generate a translation file per available locale if you specify the <tt>%{locale}</tt> placeholder.
+
+  translations:
+  - file: "public/javascripts/i18n/%{locale}.js"
+    only: '*'
+  - file: "public/javascripts/frontend/i18n/%{locale}.js"
+    only: ['frontend', 'users']
+
 To find more examples on how to use the configuration file please refer to the tests.
 
 === On the Javascript