Move Contributing to its own file

CONTRIBUTING.md

@@ -0,0 +1,27 @@
+# Contributing
+
+You're welcome to contribute to the code!
+
+## Coding style
+
+Please follow the coding style of each file.
+
+## 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
+
+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.
+
+To install the tests dependencies:
+
+```bash
+npm install
+```
+
+To run the tests:
+
+```bash
+make test
+```

README.md

@@ -60,20 +60,4 @@ gnome-extensions enable nightthemeswitcher@romainvigier.fr
 
 ## Contributing
 
-You're welcome to contribute to the code!
-
-Please follow the coding style of each file. 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`.
-
-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.
-
-To install the tests dependencies:
-
-```bash
-npm install
-```
-
-To run the tests:
-
-```bash
-make test
-```
+See [CONTRIBUTING.md](./CONTRIBUTING.md).