Update contributing

CONTRIBUTING.md

@@ -1,16 +1,20 @@
 # Contributing
 
-You're welcome to contribute to the code!
+You're welcome to contribute to the [code](#contributing-to-the-code) or to the [translations](#contributing-to-the-translations)!
 
-## Coding style
+## Contributing to the code
+
+Create a new branch describing what your're working on, for example `feature/{name-of-the-feature}` or `theme/{name-of-the-theme}`. When you're done, commit all your changes and create a new merge request.
+
+### Coding style
 
 Please follow the coding style of each file.
 
-## Copyright notice
+### Copyright notice
 
 If you make changes to a file, please add your copyright notice at the top of the file, in the form `Copyright (C) YEAR Your Name`.
 
-## Themes and unit tests
+### Themes and unit tests
 
 If you add support for a theme, please write a unit test for each of its variants, in the `tests` directory, with the theme name as filename. Unit tests are written for [AVA](https://github.com/avajs/ava) and run with node and npm.
 
@@ -25,3 +29,43 @@ To run the tests:
 ```bash
 make test
 ```
+
+## Contributing to the translations
+
+The extension uses Gettext for its localization. When working on a translation, create a new branch named `translation/{language}`.
+
+### Updating an existing translation
+
+First update all the strings in the source code:
+
+```bash
+make pot
+```
+
+Then update the translations files:
+
+```bash
+make update-po
+```
+
+You can then edit the language you want in `src/po/`, either by hand or with a tool like [GNOME Translation Editor](https://wiki.gnome.org/Apps/Gtranslator).
+
+When you're done, commit both the `.pot` file and the `.po` file you've worked on and create a new merge request.
+
+### Adding a new translation
+
+First update all the strings in the source code:
+
+```bash
+make pot
+```
+
+Then run the following command, replacing `{language-code}` with the [actual code](https://www.loc.gov/standards/iso639-2/php/code_list.php) of the language you want to add:
+
+```bash
+make add-po LANGUAGE_CODE={language-code}
+```
+
+You can then edit the new `{language-code}.po` file in `src/po/`, either by hand or with a tool like [GNOME Translation Editor](https://wiki.gnome.org/Apps/Gtranslator).
+
+When you're done, commit both the `.pot` file and the `.po` file you've worked on and create a new merge request.

README.md

@@ -59,4 +59,4 @@ gnome-extensions enable nightthemeswitcher@romainvigier.fr
 
 ## Contributing
 
-See [CONTRIBUTING.md](./CONTRIBUTING.md).
+You're welcome to contribute to the code or the translations! See [CONTRIBUTING.md](./CONTRIBUTING.md).