To support localisation, I've been adding all new strings to [messages.json](https://github.com/eHealthAfrica/LMIS-Chrome/blob/c66e25c69b83879f263730fb932c4b52d7398c9f/app/_locales/en/messages.json), which can be referenced using [i18n('key')](https://github.com/eHealthAfrica/LMIS-Chrome/blob/c66e25c69b83879f263730fb932c4b52d7398c9f/app/scripts/app.js#L39-L40). What do you think?