title: set .vim home directory to something specific
body: <p>My projects are all under <code>/Users/username/workspace/my_project</code> where <code>/Users/username/</code> is <code>$HOME</code>.</p>
  
  <p>I want macvim to always have the home as <code>/Users/username/workspace/my_project</code> instead of <code>/Users/username/</code>.</p>
  
  <p>I understand <code>set autochdir</code> sets the home to whatever the current file's directory is, but this is not what I want. 
  Also I'm using NerdTree if that helps.</p>