Best way to integrate composer with CodeIgniter 3.0

[eluser]Aphax[/eluser]
@ivantcholakov, thank you for that very clear answer, I understand the way you integrate composer in CodeIgniter, but that doesn't integrate CodeIgniter itself in the composer logic (at least system/core files), and that's the problem I'm trying to solve, why I want that ? Just to separate CI's core file from my application files and avoiding "CI package" (when I mean package I mean the whole CI brick as a standalone framework with core file I will never edit) storage in my repos.

[quote author="ivantcholakov" date="1411334327"]CodeIgniter 3-dev has a setting allowing Composer packages usage. But why do you wish to make CodeIgniter itself to be a package?
[/quote]
Because I'm participating to a small open-source project where we compare PHP frameworks between each other over a blog sample, the goal is to provide the composer.json file with the framework package in it, avoiding all the framework system file in the git repo. (It's better if the user can get all the framework up-to-date core files with a single composer install command)

[quote author="ivantcholakov" date="1411334327"]
Edit: Who do you think will support and update this package? You?
[/quote]
The actual developers of CI ? I don't get your point, sorry.

[quote author="ivantcholakov" date="1411334327"]Since you start using Composer, here is what I can recommend. Forget for now about CodeIgniter as a Composer package. It won't happen soon, or maybe it would never happen.[/quote]

I believe you but... Then why is it avaible on packagist as a package ? ("ellislab/codeigniter": "dev-develop") Maybe i'm missunderstanding something obvious

[quote author="ivantcholakov" date="1411334327"]
If you commit your project within a version control system (Git, Mercurial, SVN, ...), among other things, commit the whole folder application/vendor/, your file application/composer.json and the file application/composer.lock (Created by Composer).[/quote]
Really ? I don't get this, why including vendor files into the repo whereas the main purpose of composer is to avoid code duplication/storage ?

According to you, what would be the best solution for storing CI-based applications in a repo without storing the whole CI application ?

Thanks for your help !