Document how to add a new translation locale

What needs fixing?

Hi :) Thanks for great project. Would love to see it available in more languages. Unfortunately I haven't found the docs which would explain how to do it. Would like to know what files need changing to add additional languages for this great app. Found available languages here: https://github.com/fluxerapp/fluxer/tree/refactor/fluxer_app/src/locales It seems that messages.po file needs to be added for each language in appropriate locale codes directory in fluxer_app/src/locales/ . Looking at English translation: https://github.com/fluxerapp/fluxer/blob/refactor/fluxer_app/src/locales/en-US/messages.po It seems that a person needs to change msgstr to be correct in regards to msgid - which seems to be universal. Any additional files need changing? Maybe this file also: packages/locale/src/catalog/LocaleCatalog.tsx