add internationalization in readme

README.md

@@ -41,3 +41,7 @@ If you'd like to run the development version, spectrum uses Grunt to automate th
     npm install -g grunt-cli
     npm install
     grunt build
+
+### Internationalization
+
+If you are able to translate the text in the UI to another language, please do so by either [filing a pull request](https://github.com/bgrins/spectrum/pulls) or [open an issue]( https://github.com/bgrins/spectrum/issues) with the translation.  The existing languages are listed here: https://github.com/bgrins/spectrum/tree/master/i18n