Effectively, we're all set up to distribute the plugin. Just a few things left.

Update the documentation, and add a README.md file to let people know what your plugin does (this can be copied from the intro of your plugin). You'll also want to add a LICENSE file, indicating the license under which you're distributing the plugin. You can distribute the plugin under the same license as Vim (:help license), or choose your own (GitHub has a helpful https://choosealicense.org for this purpose).

Now, you'll just have to turn $HOME/.vim/pack/plugins/vim-commenter into a Git repository, and upload it somewhere.

At the time of writing this book, GitHub is the go-to bastion of freedom for storing code (however, as SourceForge proved around 2015, times change).

Let's give it a shot:

 $ cd $HOME/.vim/pack/plugins/start/vim-commenter
 $ git init
 $ git add .
 $ git commit -m "First version of the plugin is ready!"
 $ git remote add origin <repository URL>
 $ git push origin master

Done! You're now ready to distribute the plugin, and plugin managers such as vim-plug can now pick up your plugin!