I'm trying to use composer to automatically clone a git repository from github that isn't in packagist but it's not working and I can't figure out what am I doing wrong.

I think I have to include it among "repositories" like so:

"repositories": [
    {
        "url": "https://github.com/l3pp4rd/DoctrineExtensions.git",
        "type": "git"
    }
],

and then probably list it in "require" section. It should be similar to this example but it doesn't work. It just gives this error:

Your requirements could not be resolved to an installable set of packages.

Have anyone tried to do something like this already?