title: Adding file to project which is outside of the project directory
body: <p>I have a following root structure</p>
  
  <pre><code>dir1
  dir2
  index_dir
  dir3
  ...
  index.php
  </code></pre>
  
  <p>I wanna have a project in phpStorm (7.1.3) so that I see only index_dir and index.php</p>
  
  <p>the problem is that if I create a new project via "Open directory" I will have only index_dir in my project. I would like to add the file index.php to that project and not every other directory. How can I do that. It's driving me nuts.</p>