Localization support

First, in the translation directory, check the babel.cfg.

cd translations

If you want to add a new language support, like zh-CN:

# create a new lang file
pybabel init -i messages.pot -d . -l zh_CN
# modify the zh_CN/messages.po file to your own language
# compile the translations
pybabel compile -d .

If you modify the source code, and need to update the exist translations:

# update the messages.pot
pybabel extract -F babel.cfg -k lazy_gettext -o messages.pot ../
# update the translations
pybabel update -i messages.pot -d . -l zh_CN
# then translate it and compile it

You can visit the http://127.0.0.1:5000/?lang=bg to change the frontend language.

Visit flask_babel to see more config and details.