title: Using an ssh key with composer for a private vcs
body: <p>I'm trying to pull a private package hosted on Bitbucket into my project but I can't seem to get composer to work correctly with my SSH key.</p>
  
  <p>I'm currently trying:</p>
  
  <pre><code>{
      "type": "composer",
      "url": "https://packagist.org"
  },
  {
      "type": "vcs",
      "url": "git@bitbucket.org:{projectName}/{repo}.git",
      "ssh2": {
          "username": "git",
          "privkey_file": "/home/vagrant/.ssh/bitbucket_id_rsa",
          "pubkey_file": "/home/vagrant/.ssh/bitbucket_id_rsa.pub"
      }
  },
  </code></pre>
  
  <p>When I try to run composer update I get <code>Permission denied (publickey)</code> but when I run <code>ssh -T git@bitbucket.org -i /home/vagrant/.ssh/bitbucket_id_rsa</code> I can connect successfully.</p>
  
  <p>I'm not sure if its even attempting to use the key specified because if I type random letters in the <code>priv</code> and <code>pub</code> key options, it still fails in the same way instead of throwing a file not found.</p>
  
  <p>Hoping its just a small configuration error I've made as I'm not too sure what's wrong with it.</p>