title: How to develop and include a Composer package?
body: <p>I'm looking to develop a package in PHP, but I don't want it immediately available on GitHub or somewhere. It's easy enough to include a Packagist file in my <code>composer.json</code>, but how do I add a local package into my <code>composer.json</code>? Also, should I be building the package in <code>/vendor/foo/bar</code> (relative to the root <code>composer.json</code>), or should I put it somewhere else?</p>
  
  <p><strong>Edit</strong>: I guess my question is about how everyone else writes their packages. Does every new package get added to Packagist, and then when you want to test your changes, you commit to GitHub (or wherever), and then pull that back down via Composer? That seems really inefficient.</p>