Push rejected, failed to compile PHP (composer.json) app
<p>I have tried to push this app to <code>Heroku</code>: <a href="https://github.com/seatgeek/build-artifacts" rel="nofollow">https://github.com/seatgeek/build-artifacts</a>
I have got following error:</p>

<blockquote>
  <p>Script error in /tmp/buildpack20160326-160-1njxwfv/bin/compile on or
  near line 380 remote: remote: ! Push rejected, failed to compile PHP
  (composer.json) app</p>
</blockquote>

<p><code>composer.json</code> file:</p>

<pre><code>{
    "name": "slim/slim-skeleton",
    "description": "A Slim Framework skeleton application for rapid development",
    "keywords": ["microframework","rest","router"],
    "homepage": "http://github.com/codeguy/Slim-Skeleton",
    "license": "MIT",
    "authors": [
        {
            "name": "Josh Lockhart",
            "email": "info@joshlockhart.com",
            "homepage": "http://www.joshlockhart.com/"
        }
    ],
    "repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/tuupola/slim-fake-mcrypt.git"
        }
    ],
    "require": {
        "php": "&gt;=5.3.0",
        "monolog/monolog": "~1.6",
        "tuupola/slim-fake-mcrypt": "dev-master",
        "slim/slim": "~2.3",
        "slim/views": "0.*",
        "twig/twig": "~1.13",
        "ruflin/elastica": "v0.90.2.0",
        "knplabs/github-api": "*"
    },
    "extra": {
        "heroku": {
            "framework": "slim",
            "document-root": "public",
            "index-document": "index.php"
        }
    }
}
</code></pre>

<p>I haven't found <code>/tmp</code> folder.</p>