Use your forked repository in composer.json

While waiting for you pull-request to be merged, you might want to start using your version of a package.

Make sure you switch back to the normal way of adding a package to composer when your request has been merged.

Add the following lines to your composer.json, repositories section:
(Replace the url and reference with your case).

 "repositories": {
      "MailChimpBundle": {
  "type": "package",
  "package": {
    "name": "mlpz/mailchimp-bundle",
    "version": "dev-master",
    "source": {
      "url": "https://github.com/jverdeyen/MZMailChimpBundle.git",
      "type": "git",
      "reference": "feature/lists"
    }
  }
}
  },

After that, require your personal branch.

"require": {
       ...
      "mlpz/mailchimp-bundle": "dev-master",
       ...

It seems like we need to add an autoloader option:

"autoload": {
"psr-0": {
  "": "src/",
},
"psr-4": {
  "MZ\\MailChimpBundle\\" : "vendor/mlpz/mailchimp-bundle",
}

},

Run composer update, and you're now using your forked version of this repository.