Installation library with composer documentation

Great work!

If you would like to install the select2 library with composer, you will need to add the following to the composer.json file into the repositories array:

    {
      "type": "package",
      "package": {
        "name": "jquery/select2",
        "version": "4.0.5",
        "type": "drupal-library",
        "dist": {
          "url": "https://github.com/select2/select2/archive/4.0.5.zip",
          "type": "zip"
        }
      }
    }

After this you can install the library with "composer require jquery/select2" and the library will be downloaded into the libraries folder.

Maybe this could be added to the documentation?